If all else fails, don't throw the tickets out right away. Take them home and collect them for a while. Eventually the reality may really set in as to just how much money you are actually losing.
It's kind of like with smoking. One of the best motivators for quitting is to abstain from emptying the ashtray for a week. It's usually enough to sicken even the most hardened cigarette smoker.
Or... You can always insist that stores round your change down to the nearest dollar, thus leaving you no coins to scratch the cards. As an added bonus, the employees will certainly appreciate the subtle tip.