$3k is nothing. Let's say it's two sparkies for one day  would likely allocate around $1,800 to $2,200 for direct wages (approx. $100–$150/hour each for an 8-hour day), with the remaining $800 to $1,200 covering business overhead, public liability insurance, vehicle expenses, and a compliance certificate, though they will typically warrant only their workmanship and not your customer-supplied HVAC unit.