I borrowed this from

Giant Eagle Grocery Stores Deal:
Buy 4 each 2.6 or 3.0 oz tuna (retort packaging, water or oil) at 4 for $5, receive 30 cents in fuel rewards. Each 10 cents in fuel rewards carries a max value of $3.00 at Giant Eagle GetGo Gas stations (.10 off max purchase of 30 gallons; check website for closest location); 30 cents = $9.00 in fuel.

you can take gas cans to reach the 30 gallon limit, but only 1 car can be fueled per transaction.

Deal may be redeemed multiple times on the same receipt; One guy on Fw claims he purchased 100 packets of tuna @ Streetsboro, OH location for a total of $7.70 in Fuel Rewards ($231.00 in free gas)

Btw, Giant Eagle has not restricted the quantities for this item- as of (7/21)

Link to Giant Eagle Website