I don't know about you but I'd recommend going into a Skype call with him and record everything with Fraps, bandicam or another recording software just to assure he wont scam.
If he scams you as I said you have proof, you can get him banned. Unfortunately it doesn't mean you get your stuff back as it's untraceable.
I wouldn't do the deal if I were you. Scammed 150$ is a lot.. He scams, and although he apologized he still does it from what i've heard. Don't test him, I wouldn't take any chances..
That's a lie That's another lie - you are not even trying the least bit to gain trust from other people, you still scam, not trying to be rude but it is the truth.