I trashed the battery in my Z3 and had to get an OEM one from BMW so the price seems about right . I don't think much else will fit will it ?? Try crossing the line to Bellingham or so and check their prices. I've been getting stuff at 2/3 the price from Arizona. (I'm not suggesting you go to Az , it's just that I go there fairly frequently.)
Check the dealerships websites , some of them have online parts ordering or 1-800 numbers.