Memory allocation to users with wordpress

Hi,
I am working on a site where I need to integrate a feature so that each registered user subscribe for packages with different memory limits to upload images.
Basically project is a photo gallery site where users can upload their photos and create galleries, but they all need to pay ( purchase packages) to upload photos. Site will have different packages with different upload limit like packages 1=250MB.
I am stuck right now as i can not find any method to integrate this feature on site.
is there any method to calculate used space by users and allocate space to them?