I’ve never bought an expensive horse. I’ve sold a few mildly expensive horses. If you are rich, you can buy an expensive horse. If you are not rich, you must go and kiss a lot of frogs. You have to “shop around”. You have to look in places that other people are not looking. You have to look in people’s back yards, in “unlikely” places. You have to avoid looking in places that sell expensive horses, with gardeners working full time to keep the grounds looking fantastic, because if you buy a horse from these people, they are dumping a bad one on you for cheap. You have to look at horses whose current owners may not recognize their horse’s potential value. Just because a horse has not performed at the discipline you are interested in previously, does not mean that that horse may not be a super talented athlete, who simply has not had the opportunity to show the world what he can do yet. The horse may not be a “fashionable” breed, he may be a plain colour. These things are perfectly acceptable for what you are looking for. But if he’s broke to ride, and you feel comfortable riding him, and he feels good underneath you and moves like an athlete, if you can try him over a free jump and he likes it, does it easily, nice form, he may be the gem in the rough you are looking for. Some of the very best horses in competitive history have a background just like this, and they are not expensive to buy, yet “take to” the new sport discipline easily, quickly, and are not difficult for a decent rider to “bring on” in competition. How far you go in competition depends on the horse, and on you.
Myself, it is the racetrack where I have found my new prospects. Don’t rule this out, find the right one from the right trainer who has ridden the horse correctly, and it’s not difficult to bring one of those on as a sport prospect. This is what all the teenagers used to do in decades past, and most were quite successful, both learning as they go. Don’t think that you can’t do it too. You just need to select the right one, from the right trainer. Other than OTTBs, there are many other breeds and sources that you can look at, on ranches, in different disciplines. Don’t rule a horse out simply because he hasn’t had the chance to be tried yet. Go and try him, source him out from somewhere that rich people are not looking. Find one that “speaks” to you, and says, “I am the horse you are looking for”.
Do not go into debt to buy a horse. Do not spend more money than you can afford to flush down the toilet. If you are rich, you can flush quite a bit of money down the toilet, and be OK with doing that. If not rich, understand that you must shop in a different location for the prospect you are looking for. Good luck, happy shopping.