We bought a relatively cheap cover (around $2-300) a couple of years ago, but found it went to pieces in the sun. It was made from that breathable non woven fabric. Needed a step ladder to get it up and then pulled it as needed.
One problem we found was it got caught on a couple of the corners of the top, and tore easily. Put me off cheap covers and as our grandson as just rented a place for 2 years with a 9x9 mtr shed we can store it there. After that I'd probably get a lightweight canvas one which could cope with the weather.
Incidentally, while it was covered, the front vertical edges of the van went yellow in places. Don't know if it was the cover(grey0 or just sunshine which did that. Haven't been able to clean it us, even with proper fibreglass rerstorer.