I don't think you should fk around. At 80% rh your are gonna have problems.
I have 4 dehumidifiers and have purchased them all used for $75-125 each. They all still work too. I didn't think it was that important until I got attacked by powdery mildew.
If your RH level is always high, 50% and higher, you should get a sulfur burner and treat the entire room every 10 days. They sell burners on ebay for $70 new.
If you spend 2-3 months on these things, it hurts to just throw them away. The mildew can be contained, but you can't get rid of it once it attacks a plant