Sheila's Sports Shop is a very popular sporting goods store, which has a yearly revenue of $600,000. Sheila runs the business herself. Her alternative employment options are to be a college swimming coach for $50,000 per year or a construction worker for $40,000 per year. Sheila spends $230,000 purchasing goods for resale to her customers. She also has four employees, who each earn $25,000 per year. Sheila owns the building that her Sports Shop is housed in and she could have rented it out for $20,000 per year. Sheila's costs for resources bought in the market equal.