I think it is a great idea. Although i have to admit I'm one of the worst about saving but i really do try. I started a separate savings account. I have a set amount of money pulled out of my check each payday and deposited into that account, kind of like a christmas club but i can get it when I need it. I use mine to pay for grad school, trips, and unexpected emergencies. So when i get the good deal I have the money to pay for it. After the first couple of pay checks i got used to having less spending money and it hasn't been a problem.
I have a girl I work with that every night she and her husband take all the change from their pockets/purse and one single dollar bill each and put it in jar. They do this faithfully everyday and they are have money to pay for their trips.
Another one, this one from my mom who did this when she bought a new washer and dryer, is pay for something that you don't normally pay for. Like when you do laundry put the amount of money you would have spent to do the laundry into a little container that you are not allowed to touch until you put it away or use it for your trip.
Hope this gives you some ideas.
tara