How much are people paying for an underbody respray including some light prep work?

I'm going for body colour, only surface rust in a couple of places - very light but will need a load of road crap removing and wants the underseal tidying in some places where it has started to peel at the edges.

Also, if anyone has a dolly for moving a bare shell around that they are finished with let me know as I'm looking to buy one, car is a sapphire cosworth.

Cheers