Luke, welcome to Permies!
We're both in New England, so prices might be similar... I used to haul brewer's grain, and charged about $0.06 per lb. but it was actually a fee per bin, regardless of the actual weight. I quit a year ago, so fuel prices were better. I think you'd be best to check out the "competition" and see what service they offer and how they charge, what their rates are, then figure out your own.
Off the top of my head, in the Boston area, there's: Save That Stuff, Bootstrap Compost, Black Earth Compost, and
City Compost... you might find some info from them.