I would encourage anyone to let the man take the expense of sending you the counterfeit money, either to a PO Box or your work address, and deliver them to your local Post Office, which will forward them to the Inspector General for felony prosecution.  The envelope and probably the money orders will have an originating address they Inspector can use.

I was selling an engine block for 400. Thought the guy was legit. He first texted me from 2342810594. So I did a quick google search came back clean. So figured it would alright. This morning he texted me from this number saying his bank made a mistake. They sent 2400. An if I'd be so kind an send back the rest. Little did he know I did another google search an read all response from all these another ppl. I knew what he was going to text me before he did.  So I'm getting this check in mail should I shred it or take it to the police?