Where do I store user's files?

I have a ASP.NET system that creates files (> 2开发者_开发问答0 MB) for users and stores it currently on a folder in the web server.

You could use Amazon's Simple Storage platform:

http://aws.amazon.com/s3/

You could store your files in a SQL database as blob fields.

Bandwidth of 300 GB signifies the amount of data they will let you transfer per month before they will cut your site off or start charging you per GB (depending on who the provider is)

Get a cheap hosting plan with another provider that offers unlimited bandwidth and file storage and create a secure service that accepts file requests. Then every time you want to save a file just make a request to your service.