Depending if the furnace already has A/C and the A coil can be used again.

If you want to add AC to an existing system, it is almost as cheap to simply update your heater too, as they have to remove it to add the A-coil.

Different people have different experiences I guess.They replaced my HVAC interior coil, fan, exterior capacitor, compressor and fan for $180 (service fee plus freon).Replaced my fridge due to a door warmer that went out.  

My window company charges an extra $40/window to coil wrap them.

Replace it with an Aluminum Coil unit.

HVAC company says I have a leaking condenser coil and suction line near case coil.

However, if it is a higher-end environment you could upgrade the oven to get rid of the coils and a nicer looking sink and faucet.  

Is that from back dripping condensate leaving the cooling coils?

I change the filter myself every month so I'm not too concerned about the inside coil being dirty.The HVACs in my two new construction rentals have 10 year warranty on parts and labor.

Lots of coils and gears and coggs and kraken and victorian etc