CDE, Inc. contracts with a supplier for the fabrication of trade show booths and displays. The contract is on a cost-plus fixed fee (CPFF) basis, with the supplier's agreed-upon fee set at $15,000 and the estimated allowable cost of materials set at $20,000, for a total of $35,000. The supplier is able to bring down total material costs to $18,500. Given this situation, how much can the supplier bill CDE for the project?