Is it true that it was sold for $10? There’s a common phrase in Texas deed transfers similar to the below which just means “The sale price is none of your business”
Common Texas boilerplate: That for and in consideration of ten dollars ($10.00), cash in hand paid, and other good and valuable considerations, the receipt and sufficiency of which are hereby acknowledged, the Grantor has bargained and sold, and does hereby bargain, sell, convey, and confirm unto the Grantee the following described real estate.
There's lots of places that give 99 year leases for obscenely small amounts like $10. The neighborhood church near where I grew up owned way more land than it currently used. They "leased" the land to farmer/ranchers to grow hay in part of it and graze animals in other parts. It was leased with similarly friendly terms if not the 99 year lease.
These things are more common that people might expect. Not everyone is a lawyer-esque asshole, but that does open situations up to disagreements where people respond with "should have talked to a lawyer"
Not a lawyer but my understanding is that a valid contract must involve an exchange of value from both parties