Getting money that is owed.. (small claims?)

[handsome]

A while back I posted about my car sale and receiving a check for $2,950 but with the wrong written amount ("Two thousand and fifty dollars"). Anyhow, the buyer sent me a new check... correct spelling, but wrong amount. $2,900 this time, so he still owes me $50.

The day I received it (Thursday), I gave him a call and basically said, "Hey, your check was for $2,900. Please send the other $50." He didn't call me back until today (Monday). I was taking a test in class so I couldn't pick up. He left a message saying he intentionally left out $50 to cover the cost of a carjack.

WTF? The day he came to pay for the car, he asked me if I had a carjack and I said, "No, I never had one." I thought we both understood that the sale would not include a carjack but apparently he didn't. My gut tells me he's just trying to get away with an extra $50.

Now.. I don't want to threaten him (yet) so I will make an effort to simply ask him for the money. HOWEVER, I have a feeling that he won't send it, so I need a backup plan. would small claims be reasonable for this? If so, what's the procedure of claiming a case?