Honestly I've found the best way to SAVE money and prevent myself from spending it is to hide it from myself.

Unfortunatly I have ADD.... so after I hide it, I can forget completely about it within like .5 seconds. Not even remember I put it away for like 6 months... then all of a sudden remember I put $20 rolled up on the top of a door jam or something. BAM, instant money.

I must have like $150 worth stashed around that I have no idea where or how much it is. Hey, it keeps me from spending it untill I really really need it.