Who pays closing cost on sale of real estate buyer or seller?

Everything is negotiable. In the US, the closing costs are mostly a buyer expense. The Seller has some closing costs such as commission to a listing agent if one is used, deed preparation, and revenue stamp fees charged by the state or locality. Often the buyer will have the seller pay a portion of closing costs to conserve cash, while paying a slightly higher price. Many large builders are also in the mortgage business and pay some closing costs to have another revenue stream.