Depends on breeding and prior show history obviously. For a decent bloodline Canadian or American warmblood (might be in one of the European studbooks, but probably not) that is trained, can compete at 1.20, and is in its prime years, you are basically asking a bare minimum of around 80k. That same horse as a yearling might only be 5-10k, but then you need to train it, house it for 9 years, and bet that it won't kill itself, injure itself, and actually have a working brain to do showjumping well.