If the project is done the potential on this is continuing residual income for both of us.
What do you mean by "backup my projects"? As a developer you'd usually have some kind of version control system in place (github.com/ or bitbucket.org/), which would also serve as a backup system. If you're looking for someone to keep an archive of your files, there are a number of public or private cloud providers that offer that service (carbonite, ironmountain, goodsync, etc.).
