This FSBO paperwork is needed as soon as you accept an offer, so it's useful to have a purchase agreement onhand that you can fill out quickly. Yes, you can sell your home below fair market value, legally, and likely with no tax implications beyond a gift reporting (if under the exemption amounts).California requires those selling FSBO to fill out and file many documents and forms. Several of these documents are legally binding agreements. Selling your home FSBO? California, like many states, requires its residential property sellers to disclose, in writing, details about the property they have on the market. The California Association of Realtors offers a comprehensive user guide to the Residential Purchase.