Just visit the Greenhouse, or the Dampkring if you visit Amsterdam one day. Those are some good coffeeshops. Prices range greatly between 7 to 14 euro (there are more expensive weeds .. but I don't recommend buying anything above 14 euro). expect to lay down about 10 dollars/gram for some proper, crystally bud. You usually don't buy per gram however, they often sell preweighted bags with standard prices. You usually got 5 euro, 10 euro and 20 euro sacks (the 20 euro usually contain extra). You can use google to see how much dollars that would be.