Electric indoor heater (Winchester nh)

Looking for a heater. Unfortunately I have the biggest slumlord you could ever imagine and I have had three heaters broken my house for over a year now. And even though my electricity bill is $400 a month I have a huge gaping hole in my front door the windows are from the 19 80s or even earlier you can feel the wind blow right through them so I'm trying to find the most reasonable thing to keep us warm and not cost me an arm and a leg thank you in advance for checking.