$125 a gram is a lot even if your buying by the point [.1]. But if it's good shit and you have a low tolerance all you'll need is .1 so that's 10 doses as $12.50 a dose. Maybe if you can put up the initial cash, and sell your friends .1's at 15 bucks a pop. You'd get $120 back if you sell all but .2. You'd make money if you only wanted to try .1, but that's a lot of work and risk for 10 bucks and a point of molly.
Anyways, see if he'll give you the same price for a .1 to try it. Then you can find out if YOU think it's worth it. And you know the prices in your area better than I do.