He says he's already going to be in town so the distance he travelled to get there is irrelevant.
And this removal thing is probably going to take five minutes or less after he walks in your door.
Ultimately, I think it depends on how much you usually pay him for his time prior to this point. If you've been paying him $100 per hour then I would give him $40 or so. If you've been paying him $50 per hour give him $20.
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If you're a zombie and you know it, bite your friend!