Yeah, don't buy in the school. Do it away from the school, or even after school on the football field or something. Somewhere where no teachers or authority figures will see you for 5min or so, but even then you run a risk because you never know who is watching. Just be careful.

If this person ripped you off once, what makes you think he is actually going to give an 1/8? Good chance he'll just do it again. Be careful, cautious, and LOOK at it well before you buy. Get a scale, and you'll be set. :thumbsup: