The lowest price per can is the 4 cans for $5.60 offer.
To find out, you can calculate the price per can for each offer.
- For 2 cans for $3.50, the price per can is $1.75.
- For 3 cans for $5.00, the price per can is $1.67.
- For 4 cans for $5.60, the price per can is $1.40.
- For 5 cans for $7.50, the price per can is $1.50.
Therefore, the lowest price per can is $1.40, which is the 4 cans for $5.60 offer.