if you wish to maximise the value of your bikes, you need to find someone who wants that exact specification of bike (so some older off-the-peg bikes in standard condition are worth more now than when they were new...) or you could consider selling the parts separately.
Quite a few complete bikes (with nice framesets) often sell for about the same money as the frameset alone. Probably this is a side-effect of the fact that everybody likes slightly different things in 'nice bikes' unless they have a hankering for a specific off-the peg model as per above.
The parts are usually worth ~1/4 to 1/2 the new cost if they are good quality and in good condition, which can be a fair amount.
Well known high-end branded bikes will go for good prices on ebay because they are easy to search for and there is a ready and waiting following. I only know about Thorn (there are of course other sought after brands) but these always fetch good prices. More generic bikes struggle to find a buyer let alone a good price. What I do believe however is that (apart from the aforementioned ones), bikes are generally under valued: excellent touring bikes, even newish ones, for instance go for a fraction of their new price and I think most sellers are generally disappointed at what they can get. Second hand prices are further depressed by discounted new prices. Do remember too that bikes come in different sizes so even a keen buyer may be unable to purchase. Delivery and collection are issues too - if you're not prepared to box it up, few people are prepared to travel to the other end of the country for a £300 bike. My recommendation would be a sale on ebay but with a well prepared and detailed description - provenance and history matter and help to secure a better price. My impression is that most reasonable bikes settle at around £250 - £350.
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
Due to moving house soon I would rather get the bikes sold whole to save me having to strip them. For one of my bikes I have the original box (but I have only had it three years) and I have boxes suitable for the other two so postage is not too big of a problem.
The bikes are:
1) An Identiti single speed bike, size Large, in orange, in good condition, bought from Charlie the bike Mongerer. 2) Massi (Spanish make) mountain bike, front suspension, disc breaks, blue and grey, in ok condition but could do with a little TLC. 3) Giant Boulder (a cross between a montain bike and a commuting bike), its about 15 yeas old, in full working order, showing some signs of age, no suspension V brakes, in blue and grey.
I have photos of them all but not here at work will upload a couple of each bike later.
Lonely recumbent rider
HP Velotechnik Street Machine GTe Metabikes Metaphysics Hase Pino HPV Velotechnik Scorpion