I love a good spreadsheet. All those numbers lined up, the potential to create graphs, data upon data upon data. Phwoarrr!

It may have been that unnerving love of numbers which led me to get a little bit obsessive in my search for the UK's cheapest 0.25 carat diamond engagement ring.

So why 0.25 carat?

Well, during my hunt for an engagement ring that I could actually afford without selling my body parts, I decided that 0.25 carat was the smallest size diamond I would be happy buying.

As it happened I bought a ring that was around 0.35 carat and was very happy with it, but I felt that anything above a quarter carat was acceptable. Below that size and you really are squinting to see the diamond and above that size people will start to call it 'delicate' or 'tasteful' rather than 'small' or 'what diamond?'.

I ended up looking at 45 online jewellers and found prices ranging from £55 up to £950. 

Yes, there was certainly a variation in quality but it wasn't necessarily the case that the most expensive ring was the best one. 

The top couple of results were admittedly somewhat invalid as they were second hand rings. There's nothing wrong with buying a second hand diamond (we've covered that topic in this blog before) but I appreciate that a lot of people wouldn't consider it as an option (myself included, if I'm honest).

So, let's exclude eBay (£55) and Etsy (£95) for those reasons. 

Our winner then, on the day, was Amazon which had a 0.25 carat diamond ring with a fairly low grade clarity and colour for £221.

Let's carry on down the list though, because some people will be keen to get a reasonably high grade diamond ring, even if they are searching for a smaller diamond.

Well, the cheapest 0.25 carat ring which I would say was at least in the mid range of grading was from Purely Diamonds and came in at £350. It was an SI2 clarity, H colour diamond, so not mega high grading, but somewhere in the middle at least (if you're looking for the highest grading possible in a 0.25 carat diamond ring then I'd try Aspire Diamonds which offers D colour, IF diamonds for around £1300).

And what if you don't fancy buying from a jeweller which mostly operates online? After all, you may end up taking it back (although let's hope not).

Well, in our comparison, the cheapest 0.25 carat diamond ring from a high street jeweller was £270 from Argos.

And the most expensive? Well, that Aspire Diamonds ring at £1300 was obviously way more expensive but it's not a fair comparison as the quality is so different. 

A more comparable diamond to the one on offer at Amazon at £221 was one for sale at £950 at Beaverbrooks.

But then again, Beaverbrooks offers the prestige of being an established luxury jeweller and the convenience of high street returns. And wouldn't you rather present your diamond ring in a Beaverbrooks box?

I'll leave it up to you to decide what price you put on that.

I’ve taken a break from my usual penny pinching and bargain hunting recently, with a new guide to the best places to buy expensive engagement rings. 

Really, what I mean is the best places to buy very high quality engagement rings but they also tend to be the most expensive rings (and Google prefer the search term ‘expensive engagement rings’ for some reason).

I was curious to know how much the UK’s most expensive engagement ring cost. Or more specifically, the most expensive engagement ring that I could buy online there and then, rather than a diamond locked away in a safe somewhere in London which is owned by a billionaire.

Most of the expensive rings I found were a similar price to a new family car – somewhere between £10,000 and £25,000. The priciest ring on Purely Diamonds was a top quality 1 carat diamond going for £13,000 whilst Aspire Diamonds went up to £11,000, Beaverbrooks went up to £26,000, Shining Diamonds was £12,500 and Goldsmiths top priced engagement ring was £15,000.

A few online jewellers had rings for the cost of a sports car - sites like Diamond Heaven  went up to £49,000 (for a 2.5 carat diamond), and bizarrely CostCo (which I'd normally associated with bulk buys and discounts) had several rings around £40,000 - £50,000 with one for sale at £90,000. 

Amazon had a few rings priced around £100,000 although they were third party sellers rather than actually sold by Amazon.

Finally, I struck gold (or diamond I guess). Steven Stone had a diamond which was nearly 10 carat going for £1,383,437 - ten times the next highest retailer.

There's another twist though. I checked again a few days later and the highest on offer had dropped to £315,349 - a million pounds less than the most expensive ring just a few days earlier.

I like to think someone had bought the £1.3 million pound engagement ring. More likely, it was taken off sale for some other reason, but if you see a Steven Stone salesperson with a very wide smile this week, you'll know why...

I rather suspect that some men are postponing proposing to their girlfriend's because they think they can't afford it. 

Sure, weddings themselves can be pretty pricey once you start inviting all your aunts and second uncles but getting engaged doesn't need to be. Whilst the average spend is pretty high (between £600 and £1700 depending on which survey you believe), it is perfectly possible to get a cheap engagement ring for a similar price or even less than an XBox One.

As I write this, a new XBox One will cost you around £230, so that's the budget I'm going to work to. 

First stop, I'd suggest is Amazon where you can (at the time of writing) pick up a 0.33 carat diamond engagement ring for £199 (the price varies depending on your ring size, but most sizes are within my £230 budget). That's not a huge diamond, but it isn't particularly small either so it will look perfectly respectable for most people.

Of course, size (or rather carat/weight) isn't everything with a diamond ring. The quality - or grading - of the diamond also matters and for a low-end budget you won't get the highest graded rings. My (somewhat controversial) view is that for most people, the differences will not be especially noticeable until you either use a magnifiying glass or you start putting vastly different diamonds alongside each other. 

If you'd rather buy from a jeweller which has high street stores (making returns easier) then take a look at Argos. Their prices do fluctuate with sales and promotions, but I've seen 0.25 carat diamond rings on offer at around £225. 

If you're feeling a bit more adventurous, I'd consider buying from a US jeweller. You'll have to pay customs fees, but the prices at a retailer like SuperJeweler sometimes make it worth the hassle (check out the blog on importing diamonds for more on this).

Finally, I'd look at the second hand market. With an XBox budget you'll be able to get something which originally retailed for around £500 - £1000. It's up to you whether you (or your potential spouse) would be happy to wear preloved jewellery. I'd start by searching for diamond engagement rings under £200 on eBay.

So, if the cost of the ring is putting you off - but you think you can afford an XBox One - then I'm afraid it's no longer a legitimate excuse...

Happy hunting, I hope she says yes.

We've talked before on this website about the myths surrounding how much men spend on engagement rings.

Jewellers would like you think that it is one month's salary or even two months or three month's salary (see this BBC article about the work De Beers did to create that 'tradition'). 

But hang on a minute - it isn't. It's nowhere near.

In the UK, the average salary is around £27,000 at the moment which works out as £2250 for one month, £4500 for two months or £6750 for three months (assuming the 'tradition' is salary before tax id deducted).

But people just don't spend that much money on engagement rings. 

No-one seems quite able to agree on exactly how much proposers are spending, but everyone agrees it isn't that much. Recent surveys for average engagement ring prices came up with the following figures:

• £573 (This Is Money, research by Allianz, 2016)
• £1329 (Marlows, 2012 - this one also concluded that men in Wales spend about £600 compared to £1600 in London)
• £1231 (Daily Mail, research by LV Insurance, 2012)
• £1576 (Men's Health, source unknown, 2007)
• £1772 (You & Your Wedding, 2015)

So, from those numbers we can conclude that whilst surveys come up with wildly variable numbers, none of them come close to the £2250 - £6750 range above.

Our view at the Cheap Engagement Rings Guide is that you spend what you can afford, rather than what you think you should spend. Sure, you want to get something decent and you don't want to scrimp too much on something which should last for decades, but you also needn't feel you need to start off married life heavily in debt. 

It's also not really true that you get what you pay for with an engagement ring. Of course, a top quality ring will cost top money, but you will also find two diamond rings of a very similar quality being sold for wildly different prices.

Just take a look at our price comparison charts for 0.25 carat diamonds, 1 carat diamonds and 2 carat diamonds. You need to look carefully at grading (see the guide to 10 things you need to know when shopping for cheap engagement rings for more on that) but the profit margins applied by jewellers vary massively.

So, work out what you can afford and then take a look at one of our guides which cover what you can get on an engagement ring budget of £100, £200, £300, £500 or £1000.

Happy hunting, I hope the answer is yes!