On the look for handy hints, Jim Hamm found this site: How to sell your iPhone for the most money (infographic) His comment, "If you should be interested in selling an older iPhone, here is a nice analysis of values." It was posted 9-1-13.
Jim Hamm provides this very important information. Before you sell or give away your Mac there are definite steps to take to protect your information that's now on the computer. The article here http://macdailynews.com/2013/08/05/apple-explains-what-to-do-before-selling-or-giving-away-your-mac/ also tells how to return your Mac to its original "out-of-the-box" state. Read this from Apple dated 8-5-13: http://support.apple.com/kb/HT5189
The headline asks, "Got an old iPod? Seven ways to offload your used electronics for cash." That got PMUG Prez Art Gorski's attention, and he passes along this Arstechnica site. The article describes these companies: Gazelle, Amazon, NextWorth, uSell, Totem, Apple, Radio Shack. There's 58 comments to look at, too.
Before you sell or trade your Mac there are some important steps to take. Jim Hamm sends this article. Backup, deactivate and deauthorize, then erase. Read about Zero Out Data and 7-Pass Erase procedures.