BC is a manufacturer. During the year 20xx, ABC: (1) received cash of $800 from its customers; (2) paid cash of $600 to cover operating costs; (3) borrowed $100 from a bank; and (4) paid XYZ cash of $300 for a machine. Assume that the previous list of transactions/payments/events is complete, that ABC had no non-cash revenues or expenses during 20xx, and that all of ABC's cash is excess cash. ABC's free cash flow for 20xx was: