Want to go through that math for me, Paul?

I don't think so. Playing a coupon and your dollar, for each hand or spin you risk one of your dollars. You are guaranteed a dollar back, have a 50-50 chance of ending with two dollars. You risk losing the hand entirely one hand in 18 (if you're playing double zero roulette).

Expectation is (.5 x $1) x 17/18 or about 47c per spin. If you can do it with $5 bets, expectation is $2.35