I do, been selling books on Amazon for years, its great!
The charges are worth it and don't add up to much, I end up making money on books that are for less than $1 bc they credit $3.99 for shipping. The key is to request "media mail" at the post office, the cost is less than the options they give you and you have to request it they don't ask if its a book or cd. the most ive paid for a book with media mail is $3.50 bc it was a really big heavy book, most of the time its around $2, small books sometimes less.
I am lucky bc I get a steady supply of texts books from my friends and family that are in college. text books from current college courses sell fast and more $.