Bowfin are native to North America and are not considered a gamefish species. You should check with your local officials and ask for a citation out of the law as to how they may be kept or collected.
Bowfins are found in weedy water, generally unfavorable to most fishes. They eat anything. The few that I have caught crushed the treble hooks and starting sawing through the pastic bass plug. The other basically destroyed the Rapala.
Bowfins spawn at particular times of the year. You might want to check with fish farms that handle bass and panfish and see if they know of any dealers. The aforementioned fish and game officials may have heard about where you can get them. Alternately, you could get a seine and see what you catch in boggy ponds and rivers.
I found one reference for $25 for a 6" hatchling, with $27.50 shipping, available only late spring. We are now early summer.
Thought for the day: Celebrity Death Match, Bowfin vs Snakehead!
I think they are great fish from the Cretaceous.
If you really get stuck, I know of a few aquariums that I could call and make inquires, but thats a long shot.
