I'd rather pay for the cheap filters than deal with bigger issues like coil cleaning. 

There will probably be a couple that bring up the point that that changing filters every month or the A/C coils freeze doesn't sound quite right, just as is being done here.Having a regular HVAC guy inspect the setup from the start would have kept this a nonissue.

If the thermostat is set too low it will develop ice/frost on the coil inside of the unit.

The most common issues are dirty air filters, bad capacitors (usually go out in summer and can be ordered for less than $10 on Amazon), bad breakers (usually trip in winter with electric step heat), dirty coils (I clean coils during tenant turnovers), bad thermostats, and low refrigerant.

I have had to clean one due to a tenant frying food all the time and clogging up the coil.  

And depending on what you want it will run into a small air handler with a coil and fan, or if you choose a “mini split” there will be multiple line sets running to the “heads” basically the fan and coil all in one that mounts inside the room and looks very nice.Depending on the square footage and what the original heat pump was (air handler with duct work already installed?)

The 2x4s in the pictures are just nailers, used to add very little strength, mostly to hold the joists up during framing.

For AC systems I have a wonderful local AC company in my town do two services a year... one in spring and one in fall... they make sure the filters are replaced, blow out the condensation drains, clean the coils and make sure all is well.

All new fixtures. 5000 Replace improper basement ductwork 3225 A/C coil and condenser 3200 Stairway into basement - bring up to code 2250 Washer/Gas Dryer (stacked) 1800 Paint throughout 1500 Transfer taxes 1200 New carpet - stairs and both bedrooms 1000 Gas water heater 800 new fridge 800 Exterior paint 800 Demo/creation of fridge location 725 Replace wood rot along roof line and cap with metal 700 Roof coating 700 new gas stove 600 Trim repair, doors for both closets, door for 2nd bedroom 500 Window blinds throughout 300 Minor siding repair - rear 200 New screens 150 Total costs 34200 Offer ALL CASH 21799

Cleaning the air handler coils when dirty, changing filter, using A\C pan tabs, blowing out the drain line with shop vac and using chemicals to deter growth in drain lines all seem to help.