But getting to this stage has been a monumental hassle – far more so than I’d anticipated. When I volunteered for the £250 Challenge I thought buying second-hand would be easy: just scout around the various classified and auction sites, visit the local second-hand shops, draw up a shortlist, fire off a few emails, bish bash bosh, job done.

eBay the better

My first reality check came when I discovered the extent to which the second-hand market has coalesced around eBay. It’s not the only game in town – Gumtree and Craigslist are obvious alternatives, and after my last post some of you kindly directed me to sites specialising in refurbished and overstock machines, such as IT Auctions and ITClear. But next to the thousands of systems on eBay their listings look very sparse. And while High Street shops like Computer Exchange offer instant gratification, their stock is generally even more limited.

There’s one obvious reason for eBay’s dominance: having got into the game early, eBay has benefited hugely from the network effect. Buyers go to eBay because that’s where the sellers are, and vice versa. But it’s not just the range of items that makes it a winner: as I browsed around I quickly found that eBay’s search templates and filters made it easy to drill down to the products I was interested in, while other sites left me browsing through irrelevant ads.

Plus, when I found an eBay listing I liked, I felt confident the item was still available, which is more than I could say for the week-old classifieds that turned up on other sites. In short order, the clarity and convenience of eBay won me over.

Auction stations

But eBay wasn’t a perfect solution. The first problem I hit was that with auction-type sales it’s almost impossible to stick to a budget. When I placed bids on systems close to £250, the price inevitably crept over my limit and someone else ended up winning the auction. If I focused on cheaper systems I ran the risk of paying over the odds for a clapped-out old banger of a PC.

And of course, when you lose an auction you’re left simply waiting around for another suitable one to conclude, which is a huge waste of time. I wrote off much of Friday and most of my Saturday trying (in vain) to sneak a bargain under the hammer, before giving up on auctions altogether and switching my attention to the “Buy It Now” listings.

We want it now

This brought its own complications. Though eBay is best known as a site for private sales, it also hosts tens of thousands of “eBay shops”, through which back-room merchants peddle refurbished and custom-built PCs (and other goods), normally on a fixed-price basis.

There’s no particular harm in buying from a reseller like this – indeed, they may well be more knowledgeable and organised than your John Smiths looking to make a few quid off their old Packard Bell. But for me to do so would hardly be within the spirit of the £250 Challenge… so once I switched to “Buy It Now” I was left wading through thousands of commercial listings trying to find a bona fide individual from whom to buy my system.

Sell me lies

On the way, incidentally, I noticed a shocking amount of flagrant mis-selling, normally from unscrupulous resellers looking to take advantage of ill-informed shoppers. A favourite trick was to multiply the processor speed by the number of cores, so a 3GHz Core 2 Duo would be advertised as a 6GHz CPU (indeed, I saw several Phenom systems advertised with a remarkable clock speed of 10.4GHz). Base systems would often be advertised with a photo showing a large TFT monitor. Other product images were superimposed with bogus awards or company logos. I noted several unauthorised uses of the PC Pro masthead and award logos, none of them relating to products we’ve actually endorsed.

And when I did find an honest-to-goodness private seller, the item was all too often listed as “collection only” – raising the effective price and throwing a side order of inconvenience into the bargain (unless you’re lucky enough to live next door to the seller, which isn’t likely). Most annoyingly of all, several advertisers thought this constituted “free delivery”, and advertised their items accordingly.

Time, time, time… see what’s become of me

Eventually, at mid-morning on Sunday, I found a system that had a reasonable specification, at the right price, from a seller who was willing to deliver. Needless to say, I leapt at it. The transaction itself went smoothly, and, assuming the seller is as good as his word, it should be with me later this week. Looking across at the systems David Bayon and Mike Jennings are putting together, I think it might measure up rather well.

But though it looks like my tale has a happy ending, it came at quite a cost. Before you start scouring eBay for your next computer, remember just how many hours I ended up sinking in pursuit of a system that was right for me. You’ve heard the old canard about Linux: they say it’s a great way to save money, so long as you don’t value your time. Well, the same applies, with knobs on, to buying a second-hand PC.

The precise source is up to me: I can scour classified ads, place bids on auction sites or even try to persuade David Fearon to sell me one of his cast-offs. But the PC I buy has to be pre-loved, and it has to come in at £250 or less.

I admit, it’s not an approach I’ve tried before. Being by nature an impatient sod, my usual purchasing strategy is simply to march into a shop and slap down a credit card. This will, I suspect, be a learning experience for me.

But that doesn’t mean I have to go into it completely blind. So, dear readers: what should I be looking out for? Share the benefits of your experience, and tell me your tips and warnings.

Otherwise, on my first foray into the second-hand arena, I’ve every chance of getting screwed around and ripped off. And you wouldn’t want to see that, would you?