Jiro, Inc. manufactures a variety of heating and air$-$conditioning units. The company is currently manufacturing all its own component parts. An outside supplier has offered to sell a thermostat to Jiro for $$20$ per unit. To evaluate this offer, Jiro has gathered the following information relating to its own cost of producing the thermostat internally:

$\backslash$table$[[,$Per Unit,$15,000$ Units per Year$],[$Direct Materials,$$6,$$$90,000$