How much is it usually to neuter a large dog?

I have a purebred rottweiler male, around 95 pounds and 2 1/2 years old, who needs to be neutered. We live out in Laguna Niguel, CA and the Petsmart we called said it would cost about $500 for him to be neutered. I honestly think it's too much, but I could be wrong. What's the normal price for neutering, and does anyone know if there are any places that could neuter him cheaper and still give the same quality care?