I like the idea of a quest on top of a monetary reward. Some rare ingredient the wotch needs like a purple blossom that only blooms on a mountain inhabited by (insert random monster). There's a lot of great possible hooks. Maybe she'll do it if you bring her the eyes of a merchant who recently ripped her off. The merchant happens to be shady and is always well guarded by mercenaries expecting trouble. AH the possibilities. I use my treasure generator that is based off of D&D monster manuals, exchanging Platinun for Gold, Gold for Silver, And Silver for BP. But it still tends to be generous so I'd have to up the coin value quite a bit as well.