I recommend buying 1 or two females to let mature into breeding size and see if they're a pet you want to breed. That way in 2 years, if your tastes have changed, you are still flexible in what male you get. Obviously the morphs are up to you, I recommend browsing the morph list on worldofballpythons.com - my favorite thing to do is search a base morph I like and see what they can be turned into. Just to help get your searches rolling, here are some mid priced dom/co-dom single genes you might be interested in:
Pastel
Spider
Pinstripe
Lesser (or Butter, very similar)
Mojave
Cinnamon (or black pastel, similar genes but slightly diff colours)
Enchi
Fire
Some common 2-gene animals you might be interested in producing (or buying)
Bumblebee
Blue Eyed Leucistic (or Black eyed, which is a super fire)
Super Pastel
Spinner
Lesser bee
Pastave
The list goes on :)
Albino and Ghost are also interesting recessive projects that are not too expensive compared to other recessives. Do some window shopping with your son and decide what's coolest!