I am aware of some of our competitors in the A320 maintenance business who are charging $45 - $55 US per manhour. I would like to emphasize that this doesn't include the company for which I work.
There is a base rate for the check - price varies considerably depending on the type of check. There will be additional charges if the customer wants mods or other additional work - the shop rate will come into play here.
Snags are charged at the shop rate based on the manhours required to rectify them.
And all of this goes out the window if the AMO wants the work badly enough to undercut their competitors. Special deals will be worked out for good customers.
The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.