I buy my vaccines from Valley Vet Supply, including Rabies, as we are allowed to administer them ourselves here in WI as long as your town allows it, but most states don't, and Rabies must be given by a vet. It is a fraction of the cost for me to give them myself vs have the call fee for farm visit, mileage, and inflated vaccine prices from a vet, and they are the exact same vaccines. Valley Vet Supply has a list of the states they won't sell rabies vaccines to, you just need to look it up. I'm on the over-vaccination bandwagon, I only vaccinate for rabies, Tet, and WNV right now (because frankly 1 is 100% fatal, and the other 2 quite deadly as well, we live in a mosquito infested area, so better safe than sorry). If I know I will be in contact with other horses, or hauling somewhere, I will give Flu, Rhino, SS, otherwise my horses (at this moment in time) do not get those because there is minimal chance they will contract it.
Most boarding facilities will make you have vaccines for communicable diseases (flu, rhino, ss, strangles) otherwise vaccines like WNV, tet, and rabies while highly recommended, are usually at the owners discretion.