Elf Sternberg

A friend of mine (who has no credit problems, and never has, the bastard) uses his PDA for this. He runs Pocket Quicken on his Palm and immediately after every transaction he enters the receipt into his records -- or while the transaction is being processed by the clerk. If the pain you (or, rather, the Elf of next week) face is sufficient, then this could work to make it more immanent.

Another option would be to get a wallet with two compartments for cash. Load it up with Monopoly money equivalent to your budgeted amount, and when you spend something on the card, physically move the fake bills from one compartment to the other.