Bob needs a cloud based storage solution for being a digital pack rat. Leo says he should think about what he wants to store in the cloud and what he wants to store locally. If security is an issue, or if his data consists of large files like movies, then he should keep that locally.
The cheapest solution is Amazon's Glacier. This would be for things he doesn't need all the time. At $0.007 per gigabyte, it's ideal as a "just in case" scenario.