You can purchase a spay/neuter certificate at the
Friends of Animals (right side, type in your zipcode) and they will give you a list of Vets in your area that will accept the cert as payment for the spay/neuter.
The cert costs:
Female Dog Spay $90.00
Male Dog Neuter $64.00
The Vet *may* have weight limits or a few *extra* charges ontop of those prices above.
Check into it
....I would still go the gas route