If you don't mind smoking dirt weed out of a bong or pipe, a nickel can last you a decent amount of time. But anyway, this is the measurements around here:
Nickel= $5
Dime= $10
Quarter= $25
Half O= $50
Ounce= $100
Quarter Pound= $250
Pound= $1000

All of those prices are for schwag/dirt weed, and also those are pretty high, but if you don't already know a dealer, you can probably expect to pay those prices...