Waterproofish car cover

I bought a "motor trend" brand cover from walmart, at a discount price for the first one. So waterproof, water would pool on it. Very pleased for about $60 if I remember right. Easily tied on, won't blow off.
So pleased, I bought two more for my 55 chevies.
But yeah, best answer would be the plastic garage from Costco. I've got a couple of those too.