Because you acquired the home by a gift, your basis usually is the basis that your parents had in the home (what they paid for it, plus capital improvements they made over the years). It may be difficult to reconstruct this information, but their initial cost may be available (e.g., published on Zillow).
An annual payment of money by a company or individual to a person called the annuitant. Payment is for a fixed period or the life of the annuitant. Tax consequences depend on the type of contract and funding.