It depends on where you're from.
In Jersey, 20 will get you a g (1.0). Possibly less, unless it's middies, then you'll maybe get a deal and only pay 15 for 1.2 or so.

Here are some bag sizes you'd get for 15-20 here.

You can usually tell regs from headies from the look, taste, smell and feel. And uh, the high of course. Use your senses, is it really dry, few to no hairs, smells kind of blandish (totally not the right word)..if yes, it's probably mids.

Hope you didn't get fucked over.:hippy: