You can get a whole bunch of corn snake morphs for less than the cost of one BP morph. There's lots of colors and patterns to choose from.
They are easier to keep and a little easier to breed. You don't need an incubator for the eggs.
Big problem is that there are so many available that you may not be able to sell the babies unless you have a morph that's in demand.
Temperament is fine. Babies are somewhat defensive in the tub and squirmy out of the tub. They settle down as they get older and bigger. Some like to hang out like BP's and others will always be looking for a chance to escape.
The biggest issue for babies and one that I was not aware of as a BP owner is the dreaded regurge. Give them the wrong size food, stress them after eating, feed too many, look at them the wrong way, etc. and they throw up their food. It wreaks! Then there's a regurge protocol you follow to get them back on track which takes several weeks. There's a chart that's a guide for feeding that helps. Good news is they eventually outgrow this problem.
On the low end milk snakes are about equal in cost to a normal Ball Python and on the high end they are roughly equivalent to a single gene Ball Python. I have both Ball Pythons and Honduran Milk Snakes. The Hondurans are way cool animals and VERY different then the Balls. They are super active when being handled and almost never stop moving. I think part of this is nervousness and part is their inquisitive nature. As babies they can be a bit squirrly but as mentioned above they tend to calm down nicely. My three year old regularly holds my adult Hondos that are in the 5' range. The Hondurans are also a joy to feed compared to Balls. Every time I get frustrated with trying to get a baby Ball to feed on FT I go and offer my Hondurans the FT and marvel at their eagerness to feed.
I have had Pueblans, Sinaloans, Mexican and Honduran Milks and by far the Hondurans are my favorite if you want them as a pet.
1.10 Normal Ball
0.3 100% Het Albino
1.1 Dumeril boa