First, you need to check that vaccinating your pet for rabies is legal in your state/locality.
When we lived in San Diego County, CA rabies vaccinations could be bought at Petco. The animol control would accept the box with the lot number as proof of vaccination.
In other places we have lived, vaccination by a vet is the requirement. Actually I prefer the vet do it and get the other needed shots (parvo, bordetella, lyme, etc) at the the same time.
Red Dogg's father Andy Whiteman