Real Estate Gift of Equity

Let's say that your mom owns a house worth $500K but she loves you a lot so she agrees to sell you the house for $250K. The other $250K becomes a "gift of equity".

To add to Lisa's explanation on her example, the home would have to be sold to you for $500,000 and your mother would sign a "Gift Letter" gifting the $250k difference between the sales price ($500k) and loan amount ($250k) as a gift of equity.

is it only done in relations??