We can't guess on the cost to heat this, but you can get the seller to provide the utility records.

Electric resistance heat is probably the most expensive form of heat. Having it in the ceiling means that your head will stay warm while your feet are cold.

You can reduce your costs by insulating the attic -- blow in cellulose is probably the best idea. You will want an R38 or better.

See if natural gas is available there. Probably not any real point in changing to a different heat source (electric baseboard heat, for example) unless you could move to gas.

My opinion is that the ceiling cable is the worst choice of all electric heating options. And it has the highest rate of failures-- in my experience. Due probably to shortcuts taken in the installation.
If it does not fail, the maintenance cost and homeowner labor is as near zero as is possible for any automatic heat.
I have no statistics to prove the belief that it has the highest operating costs of all electric types -- but suspect that to be the case.

My best friend and his wife owned a house with what we called sheet rock heat and he thought it was a lot more reasonable than the house they have now that had a resistance heat air handler. The house they have now had more insulation also. It felt a lot warmer than it actually was in the house. I could imagine a nightmare if installed incorrectly though.

Very expensive operating cost. Ask to see owner's winter electric utility bills-Oct through April.

Any ductwork system? What about AC?

Is nat gas service available to your home?

You need to thoroughly understand the HVAC for this home and explore all options available to you.

IMO