If you do mystery shopping, you can pay for your shop with gift cards from a discount site, like Raise, and make a little more money. For example, If I am doing a Five Guys Burger and Fries and I spend 12.00, paying with a discount gift card purchased from Raise at 22% off, I get reimbursed the 12 dollars I spent, but get to "make" 3.52. Not much, but it adds up quickly if you're eating out every day. BUT, make extra sure that the shop guidelines allow gift cards.
I also put all mystery shops on a credit card to make another 1%. Except for the shops that are cash only. Mystery shopping is also a great way to manufacture spend for credit card bonuses.