A hardware store has both no-name and branded carports. Both can also be ordered elsewhere. I would write down features that are important, e.g. 9cm posts instead of 7cm, 6 posts instead of 4, and then weigh where to buy what. Possibility for painting/impregnation (no warped pressure-impregnated ones that are already curved on the shelf...) Width of the carport between the posts... You can upgrade the roof coating by changing the material, screws as well, stability through good foundations and mounting. 1500 is not cheap goods. I once had a 300 € piece: the car stood dry there too, but it looked scruffy.
Regards