Labeller Machine - Worth It?

Today at the stationery store I was tempting myself with possibly buying a labelling machine. David Allen extols the virtues of automatic labellers, but I have also heard people say that the novelty wears off after a while.

Anyway I was all set to buy the Brother $50 labeller, but it turns out that this sucker requires 6 AA's. To get a labeller with a plug, you need to shell out $120 for the top-of-the-line model. This is so evil.

I wonder if there is a safe, easy way to hack the $50 model so I can have a wire from the battery compartment into the wall. (Safe, now!)