The het males of a give morph are generally the least expensive. Het albino ball pythons, for example, should sell for an average price of $250 for those produced in 2004. However, you could likely find a yearling for the same price.
A more obscure breeder could get you one for less. However, in working with these obscure breeders comes a greater likelihood of being ripped off (you could be sold a normal ball python as a het). (of course, if you're not planning on breeding a het of a recessively inherited trait such as albinism, then there is no reason to have it as it looks the same as a normal - just get a normal)
However, I recommend that you search for small breeders in your area anyway. One might be close by for you to view the breeding stock and insure that he/she is working with the animals required to produce the hets.
Some more breeders that I personally recommend include:
Collette and Dan Sutherland ballpython.com
Dave and Tracy Barker vpi.com
Jake Sheffield albinoballpythons.com
Mark Goodson (no web site: I'm one of those "obscure breeders"