If you're among those lucky few who are eligible to upgrade to an iPhone 3G S without paying full retail pricing, here's good news: you can sell your old iPhone 3G and walk away with some extra cash.
Let's say you have the 16GB model. A quick check of Craigslist and eBay shows that the going rate for a mint-condition 16GB iPhone 3G is around $400.
Now, it doesn't take a math whiz to figure out that if you buy a 16GB iPhone 3G S for $200, you'll walk away with a $200 profit. Grab … Read more