I am sure this is simple, but I dont know how to achieve it

I have 2 drop down lists the produce values 1-3 each
and a table A B C
1 500 550 600
2 450 500 550
3 400 450 500

How do I get the value at the intersection of the row/coloum, so if the drop
downs come up with 1 & b the answer should be $550

Thanks