Where to get kit carports?

[mac nut]

I got one of those 10x20 carports from home depot. the pipe kind with the tarp. the thing is already rusting in less than 6 months. I have another larger tent style carport 20x40 that is galvanized and shows no rust after 2 years. I got it second hand from a guy that had it shipped from Oahu from a tent/awning company, costs more but worth it in the long run.