I need help with lookup.

Sheet 1 list with 3 columns: A= Product Category B= Product Codes C= Quantity
Sheet 2 list with 2 columns: A= Product Category B= Fee

I want to have on sheet 1 Column D a calculation of quantity X fee (for that
Product Category)
This is what I have in D2 =IF(A2=Sheet2!$A:$A,C2*Sheet2!$B:$B)
It works for some of the rows but most of them I get FALSE.

I think I need to do a VLOOKUP (or something else)but I don't know how.
Thanks