Product is easy. Talpirid. Try to get hold of the training DVD if you're not familiar with it.
Estimating is tough, I've always found it to be a crapshoot. It's easy when you've only got one or two easy-to-identify tunnel systems. When it's more complex I try to take my time and try to identify and separate all the different tunnel systems, and use the right number of baits per system. Don't underbid. Understand that to do it right you've got at least 3 visits to do. My minimum charge for moles last season was $100, and that's for a regular maintenance customer whose home I drive past every day. I've charged as much as $400 for a little larger property (22k).
Hope this helps.