Those prices sound about right - but the HomeCheck price is totally out of line. Our prices (which are posted online) begin at $299 for homes up to 2000 Square Feet (no upcharges for garages) for inspections, $69 for Termite Inspections, and $99 for Radon Testing. The whole package of all 3 services is $449.
It is fairly important to compare what you get for each price, from each inspector. Some offer checklist reports, some offfer detailed anrratives with digital photos. Some provide cost estimates for recommended repairs, some do not. Some offer free carbon monoxide testing of furnaces, some do not. Some offer free re-inspections, others charge (especially important if the utilities or any feature of the home is not active at the time of inspection.)
Other important questions to ask is how long the inspector that will be performing your job has been an inspector (experience is importnat). Make sure they will walk the roof (not all do). Ask questions to get a feel for the inspector to make sure that you are gettting the service you want (some guys don't like answering questions, or having you follow them during the inspection). There are lots of choices - take a few minutes, and interview the inspectors about cost as well as the other items to make sure you get an inspector who will meet your needs.
Every buyer is different - so is every inspector.
In answer to the info posted about national organizations, I am a member of ASHI and in compliance with all PA laws.