Can use to purchase fuel or even buy a gift card. Ampol do sell Amazon gift cards from memory.
Reports from the comments suggest the offer varies per account. Mine was spend $40 and get $5 back. Another user commented theirs was spend $60 and get $10 back
Activate the offer in the CommBank app and spend the required amount using your eligible CommBank debit or credit card in one transaction before the 13th July.
Targeted