Actually, the first rabies is for one year. Usually if you get it boostered on time each vaccine thereafter can be for 3 years (I think most vets use the 3-year vaccine).
Keep in mind that the reason that vets charge more is that they're doing an examination on your animal and not just...
Just keep in mind, you get what you pay for- good veterinary care and preventative medicine will hopefully minimize more expensive sick visits later on.