I don't understand this use case:

These projects are mainly side projects, or small freelance jobs I've done through the years, and I want to save them for posterity; who knows when I'll need them, right?

My solution to this problem is called tar. Just clone the Git repos to /tmp, tar up the results, and push the tarball to S3. Done. Archived for posterity for a few cents per month.

This isn't SVN anymore: It doesn't take special voodoo to host a repo. If nobody needs to push or pull from a repo, tar it up and archive it. If one person needs to push and pull from a repo, store it on that person's local hard drive (with backups, of course). If two people need to push and pull from a repo... Well, this is no longer an archive for posterity, this is an active project, and can the team really not afford to pay Github something like $5 per month per repo?

The killer feature of codeplane is cheap shared private git repositories. If you are the only person using your git repo, there is no reason you wouldn't store your remote on some random webhost (you can do this at http://nearlyfreespeech.net for essentially free).

If you want to collaborate with this setup, you would need to create a system-level account for every collaborator on your VPS (ugly) or install something like gitolite (https://github.com/sitaramc/gitolite).

The downside to gitolite is then you are running your own VPS, i.e. are responsible for security, updates, config, etc. It seems codeplane takes care of all the nonsense for you so you can get on with your real project.

As someone who had to set up gitolite because of this exact need, I can attest to the need for a service like codeplane.