Most dealers see keys as a hassle and would prefer you go somewhere else. GM can be a real pain in the [censored] about key code documentation, and a key is more time/work than selling most other parts. Also, a lot of key customers tend to be difficult to put it lightly.
I don't charge that much for a plain key, usually more like $30-40, but I'm hard pressed to do it for any less than that. People who are key addicts will see their price go up...like the used car lot that lost keys to the same Trailblazer about four times.
Thankfully, GM has taken our key code access away again, because they are once again unhappy with our documentation, and I am so happy. They sent a scolding email to us and said "key codes are a privilege" and I so wanted to respond "no, they are a curse, thanks for taking them away."
I had one lady come in for a Cruze flip out key/fob last week. I just traced it because no key codes, then programmed it for around $70 after tax...she said another local dealer quoted $300.
