Wow. The pricing runs the gamut. It’s kind of like asking how much a winning race horse goes for? It depends on how much someone paid for it, where it races, how it places, who the jockey was and whether someone wants to buy the winner. Is it winning at some claiming race on some track in the boonies or whether it’s winning the Triple Crown series, Breeders Cup etc… It’s the same for Grand Prix jumpers.
There are very wealthy people who pay millions for medalist winning Olympic horses that go to the very high end Grand Prixs and I know a horse that sold for $30K and within one month was winning and getting high placings in the $25,000 Grand Prixs. And someone had to develop that jumper and nurture that talent. But many talented horses don’t make it to the top due to injury or attitude and many get sold before they get to the top.
And one man’s trash is another man’s treasure. Sometimes a change in program, rider or even a tack change can make a loser a winner and vice versa.
So to answer your question…it depends.