A free horse is never a free horse...and really, you don't want to get one a whim just because it's free
. There is a lot that owning a horse entails, and it's not just financial.
If you ARE interested in having horses, you could always board somewhere? Flat fee, they clean/feed/water, they maintain fences and land. A lot of people kind of scoff at boarding prices (I've found maybe $250-400/month reasonable), but if you figure in the cost to maintain property for them...boarding might be cheaper.