Spend $150 on gift cards in 8 transactions = $1200 spent. (Wide variety of cards available - had to buy at least 2 different cards. EX: Esso, Petro Canada)
6500 pts per transaction x 8= 52,000 pts (not awarded instantly but awarded within a couple of weeks)
If redeemed on bonus redemption days like upcoming one or similar worth approx $125
$125/$1200=10.4%. So basically if you have to buy gas anyway, have the cash up front, and regularly buy stuff at SDM, you can save 10% on gas, or put another way 13 cents/l if gas is $130/l.