portable garages or carports?

I got the HF 10X17 "portable garage" (poles and a tent!) and it held up for about 3 years then it rotted. The cover is available alone to replace, but a better option would be to get some surplus canvas ($$$!) and cover with that. Should last much longer. Im going to clad my old frame (suprisingly sturdy) with some cheap strandboard and roof tile it for a semi permanent structure as its already staked in the ground.
If I were to start again, I would pour A 4" slab and do up a real 2X4 braced structure but money IS an object so.....of course I could just clean out my garage...;-)