You can buy rabies vaccines if you are not in a restricted state.
From Jeffers Pet's website - "Some states require that Rabies vaccines be given by a licensed veterinary professional. Many make it illegal to sell or buy. Some states, while not restricting the sale of the vaccine, refuse to recognize its validity unless administered by a professional. Please check your state and local laws before purchasing."
Also from the same page - "Restricted States: AK, AL, AR, CA, CT, HI, IA, ID, IL, IN, KS, MD, ME, MN, MO, MS, MT, NC, ND, NE, NJ, NM, NV, NY, OR, PR
, SC, TN, TX, UT, WA, WV, WY, AB, BC, MB, NB, NL, NT, NS, NU, ON, PE, QC, SK, YT, CN, GA
Note: Cannot be shipped to a P.O. Box!!!"