ftp storage hosting website /works with cpanel, must be auto

i want to make a website where ppl can buy ftp (storage) accounts (2GB) - they're should access to their files - they're should browse / download / etc.. - they're access their files on http and ftp - must be auto system (with account creatiion, account expire) - buy accounts with paypal - it should has a: login interface registration interface - file interface (for browsing, downloading, deleting, etc.. ) - some good features.. Currently i have a domain and a shared hosting with 100 gb storage and unlimited bandwith I have a cpanel and can add unlimited ftp users Please do not bid if your price is higher then 200$.. Thanks..