Sometimes, owners won't register a horse when the parents are registered because they didn't like the quality of the colt. Personally, I won't buy grade--you don't ride papers, but they often help the horse get a better home once it moves on from you. And the training is worth more--if you train a grade horse to the nines, you still can only get maybe 1000-2000 for it. But a registered horse that can go to breed shows will get a lot more.
Low priced grades (100-700) as well as OTTB sell well around here because there are sooo meny Registered horses selling for higher prices. There is very few registered horses going for under 1000.
In Ocala Fl? Really? That's a pretty big assumption. Just because the people you know are buying grades/OTTBs doesn't mean they sell better then the registered horses. Quite the opposite... all around the world.