Tenn. Code Ann. § 66-8-106

Any debtor whose interest in real estate has been so sold, and is subject to redemption, may redeem the interest by paying to the purchaser, or to anyone claiming under the purchaser, the amount bid or paid by the purchaser, with interest thereon at the current composite prime rate as published by the federal reserve board as of the date of purchase per annum, together with all other lawful charges.