Inexpensive power conditioners?

Looking for advice. I do have an expensive power conditioner for my AV equipment, but it never occurred to me to use one on my pellet stove until an ice storm ruined the $250 control board due to the fluctuating power. I need at 300w conditioner. Now I am worried about the TV's and other electronics in the house, even through they are on surge protectors. Is "OPTI-UPS SS1200 Stabilizer Series 6-Outlet Automatic Voltage Regulator" acceptable ? At a price of $20, I can protect electronics in every room.