I don’t think “free lease” means what you think it means. It is absolutely not free. It’s only free to the horse’s owner, because they’re giving YOU all the expenses.
I wish people would stop using the term “free lease” and start using the more appropriate name “care lease.”
If you “free lease” a horse, you’re typically responsible for board, training, vet bills, shoes, and insurance. And you’re committed to that for the term of the lease. So if the horse goes lame on day two of a one year lease, you do not get to send the horse home and be absolved of cost or responsibility.
Also, an off-site free/care lease is quite rare unless you or your trainer know the owner.