Mike hit the nail on the head. The mechanic wasn't the one who charged you so much, only his employer. I garuntee you that he had to pay top dollar for a tool like that. Now that he is out a expensive tool, its only going to cost him in the coming paychecks to recoup it to the tool vendor.

If you can, please return it. I'm in the same boat. I have to buy all my tools for work. No tools = no work. Its not AAMCO your sticking it to, its one of their employees.