There is a building materials street on Tianbei 4th Road, Luohu District, Shenzhen, where there are many vendors selling aluminum plates.

There is a Jindi building materials market in Xiasha, Futian District, Shenzhen, and there are many vendors selling aluminum plates.

If you need a large quantity, you'd better contact the manufacturer directly, such as Shenzhen Fangda, and you'd better contact the salesman, who can give you a preferential price.