A half O for $150-$200? Selling in dimes (1g) at $10 a piece, you'll lose money! To make any money, you'd have to sell them for $20 a gram, and then really, you'll only make $80-$130 in profit.

Buy in bigger quanitites to make some real money. All that work selling and going out, or people coming in and out, for such small profit is not worth it, plus for $20 a gram, it had better be some high quality smoke or you'll get no buyers.