The bottom line is: Real estate contracts must always be in writing in order to be enforceable. While laws may vary from state to state, most states have a Statute of Frauds that applies. And in general, oral contracts are hard to prove and enforce, so it pays to have agreements in writing.
Answer for number 6:
Generally speaking, the UCC requires that any contract for the sale of goods with a price of $500 or more must be in writing.
