DH and I sell a lot of stuff on
amazon, mostly books, CDs, and DVDs.
We NEVER sell anything for one cent. The people who do this are either power sellers (or whatever they call them--translation: people who pay amazon a hefty monthly fee and do a
huge volume of business) or people who've just started out selling and think they'll make their money back with the shipping reimbursement.
Look on amazon and see what your exact item in the same condition is being offered for by other sellers. If it's less than $4, it's probably not worth your time. Amazon deducts $0.99 right off the top of everything you sell and charges a commission on top of that.
If you're selling an immensely popular book, check on half.com as well. The fees are less (as someone already said), however, the market for books on amazon is much more active.
For CDs and DVDs, we often check the price on half.com as well, but it's quite often exactly the same as amazon's prices, when you take the fees into consideration. For example, it'll be selling for $1.00 less on half.com, which is the extra fee you'd pay amazon.
Besides books, CDs, and DVDs, you can sell anything on amazon that's listed for sale there, for example electronics, computer stuff, appliances.
Make sure of the condition of your item before you sell it and list it in the appropriate condition category. If the item has flaws, list them. Remember that a heavy hardcover book will cost you more to ship (even media mail) than a small paperback, so take that into consideration when setting your price. Sometimes heavier books are not worth it (to us) to sell, since we'd make like $0.50 profit from the sale. But only you can decide what's acceptable to you. If you have enough items, maybe $0.50 profit per sale is worth it to you.
Set a mental lowest-profit-acceptable-to-you price and when the item isn't worth that much, donate it or recycle it or give it away instead of trying to sell it.
And, finally, the best way to sell stuff is to price it at least somewhat below the lowest price already offered for the item in the same condition as yours. For sure, those are the items that sell first.
HTH.