Lots of variables go into the expected cost of a basic inspection. How well does the shop know your plane? Do they know your plane type well? Are you in a busy or competitive metro market, or a more sleepy rural airport? How many hours on the engine/airframe, etc.? My annuals have been running around $800 for the basic inspection, plus whatever it takes to bring it back up to my standards. There is always something unscheduled...fuel drains, gaskets, cracked wheel pants, ADs and SBs, etc. Average total cost each year is around $1,500, not including any avionics repairs/maintenance/upgrades. But my plane is very familiar to 1 of 2 non-metro shops in my area, the engine is relatively new, the vacuum system is gone, and proactive maintenance throughout the year keeps things from getting out of hand by annual time. It's a lot cheaper if the shop is not learning your type on your nickel, or has to go through all the AD compliance again to satisfy their standard of care. It pays to stick to 1-2 shops that work on your plane regularly, so they can trust the past paperwork. If your plane is a new acquisition, then there is often a bunch of deferred maintenance left to you by the previous owner that has to get rectified in the first few years of ownership to bring it to your personal standards, and those annuals can be eye-opening.
Personally, I'm not looking for the cheapest annual possible. I'm looking for an annual that rectifies all issues to my standards of flight safety. I don't want to be nickel-and-dimed to death, but I don't want to skimp on little stuff that might accumulate to the point of a safety of flight issue either. Finding a good balance of care and cost control with your shop is the key. Ultimately, the annual inspection itself is is a small fraction of my annual operational expense.