Jamie, the owner of 'Jamie's Port a Potty' leases 10 used portable bathrooms from Royal Restrooms. The company sets up and services portable bathrooms for long term construction projects. The following costs were recorded for last month for Jamie: $1,500 rent costs $200 emergency waste calls (2 calls last month) to construction sites $4,000 salaries for management $500 insurance $300 supplies (toilet paper, etc.,) $2,000 employee hourly wages What were Jamie's variable costs last month?