Sorry to suggest the obvious, but does your airline or union have any deals you can use? I just rented a car in YYZ for ten days. The pilot association's deal was less than half what Avis wanted and included insurance.
Rented a car from Hertz at CYVR once because I needed to drop it off in Edmonton and nobody else could do that. I don't remember exactly what I paid but I'm as cheap as the next pilot and it didn't give me a heart attack or anything. Sometimes you just gotta bite the bullet and pay though, eh?