I guess it all depends on your definition of "inexpensive"...as well as what kinds of animals you're interested in looking at. There are many, many different corn snake morphs that are very affordable, as well as a variety of other colubrids.

For ball pythons, you can often find pastels for a couple hundred dollars now. A bit more for spiders...but again, it all depends on what you call "inexpensive." Compared to a couple of years ago, pastels and spiders are VERY inexpensive.

I don't know enough about the boa market or leo morphs to comment on those.