The Indiana University Axolotl Colony will not always sell axolotls to private citizens. However, if you are able to go through a school or university to obtain one through IUAC, that seems the best/easiest way to go.
However, there are several axolotl breeders that participate in the Caudata.org community that may be able to help you out as well. (Unfortunately, I believe Michael Shrom is out of axies until next Spring?)
Personally, I purchased two of mine online from a biological supply company which will sell to private citizens.
My suggestion would be to keep an eye out in the classifieds section of this site and contact a breeder, unless you can go through a school or university to get one through IUAC.