How much does it cost to have an a coil replaced- professionally installed?

Usually 1000.00 to 1250.00 is about right with today's material and labor rates. There will be variables like is it a cased coil or just a bare A coil. Does it have an expansion valve that will also need to be replaced and then you have to recover the refrigerant usually ad a liquid line filter. Leak test and then pull the system down to remove any air and non-condensibles. After all that then you have to recharge the refrigerant. This info is given as if in a nut shell since more work is involved.