sunflower,
I had to respond, as I've used Amazon to sell loads of stuff, mostly books and cds, plus the odd dvd. It's brilliant.
It's different to ebay in that you don't pay to list something, but if you sell it, amazon take a cut, then add some cash for postage. When you see someone selling something for 1p, they're probably not making money from the sale of the item, but from the leftovers from the postage. I have to say, I've never done this as they sales have to really mount up in order to make any money out of it and I was simply selling a few unwanted items.
Amazon do this automotically and put all your profits in a 'holding area' which then downloads automatically to your bank account every 14 days. Buyers and sellers can rate each other as well, much like ebay.
With amazon, you can either sign up as someone who just wants to sell on a few items or as a small business. I think there's a threshold of 30 or 40 items, but it's been a while since I've listed anything. Small businesses, like independent bookshops, can then list loads of items, hundreds and thousands, which is why you may have noticed there are some with 40,000 ratings. I've no idea what happens with vat (none on books of course), but I think with just selling on a few items, amazon sorts it for you.
It's a very useful way of selling things. You can set your own price and also check what you're competing against and adjust your price accordingly.
As Hermia mentioned, though, free delivery does not apply so it's well worth checking your totals on some purchases if amazon is cheaper!
hope this helps.
Jo