Mark,
These guys figure they have you by the...well, anyway, I saw a guy go in a get a part and was charged over $100.00 by the guy running the yard.
The buyer said he could go through Summit for half of that, the yard guy told him to go order it...he knew this guy needed it then and he could reem him in the process.
And yes I am sure it has happened to me as well as all of us that have ever bought from a junk yard.