Need Advice About Possible Scam.?

I am selling a used GPS system through Craigslist. I got an email from a guy wanting to buy it. He said had moved for work and wanted to send me a check and have his mover pick the GPS up. I agreed and sent him my info. Now I have received an email saying that his bank made the check out for $1500 when I am selling the GPS for $50. He said he wanted me to cash the check keep the $50 plus $100 for my trouble, then western union the rest of the money to his mover. Is it just me or does this sound like a big scam?