I post ads on kingsnake and fauna, ballpythonsforsale.net, and every other reptile forum with a classified section that's got some activity. I also post on kijiji, hoobly, and oodle.
I go to local fall breeder expo each year, and have a table there.
I have previously sold some normal babies to local pet stores, but now there's only one reptile specialty store left in town, and he doesn't buy them, so I'm out of luck for that this year. (I snoop out the store carefully before I consider offering them ball pythons...I won't sell to stores with bad husbandry, of course). It doesn't matter--my normals are all gone now. I produce about 1/3 normals, and still sell them all before many of my morphs each year. Most go locally, but some folks will pay to have a good baby normal shipped to them as a pet--they appreciate having full records, and a fat healthy baby that's feeding well.
Prices depend on morph, quality, and market--you'll have to simply do your research each year.
I would expect to simply keep any animals I did not sell, but so far, it hasn't happened--I've sold every animal I've had up for sale before the next season's eggs arrive.