Just to help :
1lb = 16 ounces = 454 grams
1 ounce = 28 grams (approx. )
1/2 ounce = 14 grams
1/4 ounce = 7 grams
1/8 ounce = 3.5 grams

to find out pricing per grams:

~price (divide) grams
ex: 2 grams at $40, $40 (divided by) 2g = 20 $/g