When Target entered Canada they brought the Target RedCard with them -- a debit or MasterCard that grants you an extra 5% off every purchase. Walmart is now on the market with a Walmart Rewards card offering cash back on all purchases plus some other rewards. Here are the details of the card:
1% back in Walmart Rewards on every purchase
1.25 back in Walmart Rewards for every purchase at Walmart
When you sign up and use your card anywhere in the next 30 days, you'll get $15 in Walmart Rewards automatically
Five Walmart Rewards equals $5 in redemption value at Walmart stores in Canada. There's a chart here detailing what how a sample monthly spend works out to Walmart Rewards per year. It's a big spend, but if you're using it as your primary credit card you can slowly accumulate rewards. For pure cash back rewards, though, you're probably better off with a straight cash back credit card.