Here is an example of the spreadsheet I have:

Width Thick Cost
1 1 $20
1 2 $25
1 3 $30
2 1 $25
2 2 $30
3 3 $35

I want my salespeople to enter in the width in one cell and the
thickness in another cell and have it return the cost. I imagine I
will have to use the Vlookup function.