Multi-Zoning Temperature Control or Other Solution for Basement

[Taylor Dankmyer]

Very new to this - so hopefully my question isn't too elementary :)

I have looked at a few homes to buy with kitchens in the basement, set up for a Mother in Law suite. Some have separate entrances, or entrances that could be made separate relatively easily. However, one issue I have found is that the central air and heating is still all one unit for the 2 floors. I would be living on the main floor, so the renter downstairs would have to deal with whatever temperature I found appropriate (for airbnbs this may be workable, for a LTR, it's likely less so). In the current place I am considering, it is about 980 square feet with a living room, kitchen, 2 bedrooms (maybe 3, but i may keep one for storage). 

I had looked at some multi-zoning setups, but one (like HoneyWell EvoHome) seem to require a different setup than central air & heating, and I couldn't make sense of making it work from some searching online.

What would be a preferred or recommended route for this, given the basement is already set up with vents? Having a separate central air and heating sounds like a large investment (but I haven't ran any estimates on it). What are other good, potentially affordable options?