Answer:
I believe it would be $2 per bag normally.
Step-by-step explination:
If you take $2 and subtract $.50 it is $1.50. Take that multiplied by the number of bags he bought (4), would mean he spent $6 at Wal-mart.
Now $2 subtracted my the sale of $1, is $1 per bag. If he bought 6 bags at Kroger, 1 multiplied by 6, would equal 6. Meaning he spent $6 at both stores if the price was $2.