Easy Coupon Flip - $5 to $10/MO

Not sure if anyone else does this but cigarette coupons can go for 50% of face value on Ebay, especially top market share brands like Marlboro and Camel. American spirit coupons are great value too but they only seems to be available intermittently. Lower market share and less in demand coupons go for less and may not be worth your time.

Sign up for each manufacturer's website and visit once a month. They will usually let you order coupons once a month. Always order the highest value coupon they will offer you - usually $X off a pack. Collect two to three months worth and flip on Ebay (send to a buyer using an envelope and postage stamp, don't pay for a shipping label).

Also some manufacturers do contests and give-aways. I've won around $100 in visa gift cards over the past couple years and a few trinkets (thermos, water bottle). The give-aways I've gotten include a multi-tool, sharpening stone, and a jar of salsa (they were trying to advertise to the hispanic market).