who can I sell old books and magazines to?
There are various places where one can sell their old books and magazines. Some of these places are online stores like powells.com, Craigslist.com, eBay, cash4books.net or ckybooks.com. Amazon is also a good store to sell them.
ebay,craigslist,used book stores, or you could just donate them to a place like goodwill.