h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I thought I'd just add a note about the fact that there are now loads of auction sites on the net. However they don't seem to have the quality that ebay has in my opinion. Although I am a complete auction convert (it was great for christmas) I rarely even bother looking at other sites these days. I suspect that alot of these are due to the fact that ebay is so famous that it has become the only place to put your goods, after all an auction site is only as good as the stuff on it.

Some tips though:
If you are the seller and you recieve a cheque, wait for the cheque to clear.
Always send goods by special delivery in the UK, it may cost a bit more but you have much better security, its just not worth sending items by regular post, there is too much room for disater.
Set up nochex and paypal accounts. They are seriously useful. These are both services that allow you to pay someone with a credit/debit card through the internet, provided that they have an account. It takes a few days to set them up so it is worth doing it as soon as possible. If you pay through one of these services then the process is so much simplier and quicker.
Watch out for the end of auction. many many many people wait until the final minute or so before placing a bid so the price can shoot up dramatically or you can be out bid literally at the last minute. Its a bit rude I know, but there you go.

The process of bidding at the last possible moment is called "sniper bidding". The purpose of this is usually to avoid price escallation. Sniper bidding can be performed manually, but this can be a problem if the item you want ends at an inconvenient hour. For this reason, several web sites have evolved which can perform the sniper bidding for you. My personal preference is:
http://www.esnipe.com/
which I have found to be highly reliable. Several other sites are available, though, such as:
http://www.auctionsniper.com/
http://www.isnipeit.com/

Since eBay earns a percentage of the final price of each item, they generally want each item to reach the highest price possible. For this reason they don't want their users to know about the sniper services. eBay has been known to remove auction listings which contained links to sniper services suchs a esnipe.