I would pay $5,000, perhaps more, to never clean my bathroom again and always have a clean bathroom. My budget is a little bigger for a hobby project. I figure $10,000 - $20,000 for me to prototype something, that's including failures, etc. over 2-3 years. I have no idea how much motors cost, but I'm getting the idea that they are pricey.

Edit: if it's more than this it's not a deal breaker, I just have to rope someone else in, spread things out over more years or something more creative.