SDCL § 59-9-5: Actual authority to sell on credit, restrictions.

In addition to the authority of agents in general, a factor has actual authority from his principal unless specially restricted to sell on such credit as is usual anything entrusted to him for sale excepting such things as it is contrary to usage to sell on credit, but having once agreed with the purchaser upon the terms of credit, the factor may not extend it, nor may he pledge, mortgage, or barter property entrusted to him for sale.