Actually, from what ive found, plumbers are in generally shot supply across the world (possibly because career prospects also include sewerage technician?! O___o), so at which point, if thats one of a handful of plumbers for hundreds of thousands of households and businesses, that would make sense (not to belittle your statement - just something i found out earlier).
Crewdroog: I think you need to test the waters? or at least see what the competition is selling at and adjust from there. make some calls and get some quotes, then you can make a decision based on their rate, their skill and yours.
Tried that. If I charged what others were charging (for essentially free stuff they flopped on page), I'd be sharking people for £100s to start off.
I figure if I charge maybe £50 as a deposit (which i include my first two hours brainstorming into), and leave it at that for now, then I'm good either way. I can adjust as time passes, and whileits a fair hike on the deposit (from £30), itsnot a killer when you consider the base price of a night out for one.