Build something that works
While Amazon S3 is the most popular provider, I think beginners should start by learning Dropbox first. Amazon S3’s bucket system of grouping files, complicated permissions, and setup difficulty can be intimidating for someone new to Rails. I think it’s important to flatten the learning curve as much as possible. Students can make their own decisions on which to use once they’re more familiar with Rails.
Maybe I am wrong but as far as I know Amazon S3 is not free, although they charge you a little. Dropbox is completely free and convenient to use. Correct me if I am wrong.
Both Amazon S3 and Dropbox have free storage limits. Amazon S3 offers 5GB for free, while Dropbox gives you 2GB automatically, and up to 16GB more for referrals.
Thank you Alex for the correction.