How much can I get for my iPhone?

I have a black iPhone 3GS 32 GB and its in perfect condition. It still has the screen protector. I want to get as much as I can for it because I have a son and I don't use this phone.

Honestly, at the most, you can probably expect to receive no more than $75-100 for it. That phone is just very old and it's hardware limitations make it incompatible with newer software. You can get the best price at www.swappa.com It's like eBay but for phones and they don't charge ridiculous fees. You can also sell it through craigslist but you're better protected when you deal through swappa. Best of luck!