List your books on eBay. You will need to establish an eBay account and a corresponding Paypal account for payments (both are owned by the same company), login and then click "Sell" on your eBay dashboard. You can either list each used book and CD individually (which will cost you more in transaction fees but could end up netting you more money in sales), or you can list the books and CDs as a lot (all books for one price).
Many people choose to sell their old books and CDs by signing up for Amazon's Advantage program. With this program, you list your products on Amazon and when something is sold you have to split the sale price with Amazon. You keep 45 percent of the sale price. Simply scroll down to the bottom of the Amazon home page and click "Join Advantage" then "Apply Now!" to fill out an Advantage application. List the types of products that you plan to sell. If approved, you will receive a confirmation through email and immediately be able to list your products on the site.
Craigslist.org is a haven for people who are looking to sell off old, used books and CDs. As they say, one man's junk is another's treasure. It is free to list on Craigslist, but you will most likely have to physically meet with the buyer to sell your goods. Go to the Craigslist website for your city, click the "Books" or "CDs" link under the "For Sale" section in the middle of the page. Then go to the top right of the page and click "Post" to list your items.
Hold a garage sale on a beautiful day. Place fliers advertising "Garage Sale" with your address in your neighborhood. Label all of your used CDs and books with reasonable (negotiable) prices. Offer multiple books and CDs at a deeper discount to get rid of them more quickly.
Go to consignment shops in your local area that sell books, CDs and other small items. Set up an arrangement for the owner to sell your used goods on your behalf in exchange for 40 percent of each sale (you receive 60 percent). You leave the books with the vendor and then call to check on sales periodically. This arrangement comes with some level of risk, as it can sometimes be difficult to collect money from small consignment shops.