Shopper name: Gary
----------------------
eggs: 1 units at $1.75 per unit = $1.75
milk: 5 units at $3.39 per unit = $16.95
   ----> Subtotal = $18.7
   ----> 7% tax = $1.3090000000000002
   ----> Total = $20.009


Shopper name: Sally
----------------------
ice cream: 2 units at $4.25 per unit = $8.5
eggs: 2 units at $1.75 per unit = $3.5
   ----> Subtotal = $12.0
   ----> 7% tax = $0.8400000000000001
   ----> Total = $12.84


Store Inventory:
There are 70 units of milk in stock
There are 80 units of eggs in stock
There are 35 units of ice cream in stock