Ok, I've gone and checked them out. I saw the ones I had contacted, but saw other possibilities, including one that will do each cat for $10, since I fit their list of qualifications. I'll contact them and get some more info. I really appreciate your help! I really feel more relieved.

OMG! I just looked at some further information, and the veterinarian we took Cozy to when she was injured is one of the low-cost spay/neuter providers. I have to call them; I didn't know they offered this! Thanks again!