If you don't want to have to cart your crap around town to get rid of it, consider online avenues. The online auction house eBay is a great example. You simply sign up for an account, get PayPal good to go, and use eBay's handy reference guide to get an idea of how much your prices -- the bottom-line bidding price, the fixed price or the "buy it now" price -- should be. Pop up a couple of photos, a title and description of each item, plus your preferred method of payment and your shipping options and your listings are pretty much done. Then sit back and wait for the bidding window to close, and ship whatever has sold.
But if waiting around with your fingers crossed while the auction clock counts down isn't for you, there are other online options to get the word out that you have goods for sale.