I haven't seen any places around where you'd find one. It's really a lucky thing if you do. Someone surrendering a neutered male is unlikely and there are no rescues that automatically neuter them I think.
Alternatively, I've called around and Shady Oak Veterinary has the cheapest neuter in the area, it's $97 I think. I have boys in half and girls in the other half of my DCN. I was going to neuter them but I got fired from my job. ;-;