Check out this webpage...
Yorkie Haven Rescue Adoption Fees
It is a good breakdown of where your fees go and what the expenses are...and that is for a healthy dog. Rescues depend on the adoption fees to help supplement some of the costs, and by far, the adoption fees don't cover everything.
My friend just paid $325 to adopt a mixed breed adult dog from the Humane Society!! So, $450 for a purebred yorkie, IMO isn't super steep,especially for California.
I paid $150 for my 2 year old rescue pup, but I know I lucked out!! I had no idea what the adoption fee was when I went to pick up my little guy so I brought a lot more money than that. My jaw dropped when I found out how cheap he was because he was neutered, had his shots and had to have his baby teeth removed. I definitely plan on sending a donation to the rescue for Christmas because I know how much they did for my little guy.