That's an awkward layout with interleaved columns.
Code:
--A--- --B--- -C- --D-- -E- --F--- --G-- ---------------------------------------------H---------------------------------------------
1 Item Price
2 Burger 120
3 Fries 110
4 Shake 140
5
6 Qty Prod Qty Prod Qty Prod Total
7 1 Burger 2 Fries 0 Shake 340 G7:=SUMPRODUCT(CHOOSE({1,2,3}, A7, C7, E7), LOOKUP(CHOOSE({1,2,3}, B7, D7, F7), $A$2:$B$4))
8 3 Fries 1 Shake 5 Burger 1070