Trade in your used, functional smartphone, tablet or eReader for an Amazon gift card

Here's the situation: the iPhone 5 is due to come out in the beginning of October (rumor has it).  My iPhone 3GS still works just fine but I want the upgrade to the new version. What do I do to get the most value out of my old phone while I buy the new one?

Trade it in on Amazon.

You can trade in your functional smartphone, tablet, or eReader for high-value Amazon giftcards.  Your item must still work, be in good aesthetic condition and you must still have the original packaging.  I can get up to $130 for my black 16gb iPhone 3GS, though I think I would probably get slightly less than that, since my iPhone exterior is a little bit scratched.  That's considerably more than I can get from other trade-in services or on eBay.

Here are some trade-in values for recent older model iPhones, iPads and Kindles:

• iPhone 4S 64GB - up to $500 credit 
• iPhone 4S 32GB - up to $450 credit 
• iPhone 4S 16GB - up to $415 credit 
• iPhone 4   16GB - up to $300 credit 
• iPhone 3GS 32GB - up to $145 credit 
• iPhone 3G 8GB - up to $85 credit 
• iPhone 2G 8GB - up to $25 credit
• iPad 1 16GB, wifi, & 3G - up to $235 credit
• iPad 2 64 GB, wifi - up to $435 credit
• Kindle 2 DX - up to $61 credit

Check here and see what your older version electronics will bring in on Trade-in.