Unfortunately a cheap cover will eventually scratch the hell out of the paint if you are using it on a daily basis.
I store my Porsche for months on end sometimes. But I use a real cover. These are some of the best:
http://www.calcarcover.com/cover_about.aspx
And no, they won't burn from hot exhaust tips. But you shouldn't cover a car when it's hot anyway.
Why you are covering a white car on a daily basis is beyond me. Cars will get dirty, that's why we wash them. And a lighter car shows dirt LESS than a darker colored car. Try owning a black car.
I'd re-think your strategy, if I were you. Good luck.