So the Google drive part is completely free. BUT, it might not work as you'd like. What it lets you do is download PDFs(or docx/pptx converted to PDFs by OneDrive) and upload PDF exports of notebooks/PDFs. The problem is, it's not a sync service. So, if you download file A.pdf, write something to it, and then upload back to GDrive, you'll have a duplicate of A.pdf that's the newer version.
You can totally SSH into the device and transfer files with curl(which basically utilises the web interface) iirc, or just directly copy their proprietary files format notebooks too, altho they will be unreadable without a working third-party tool for that version. What I'd use the SSH for is full notebook backups rather than a normal way of transferring. Then again, I do have toltec(the community package manager) on an older version of the OS to run a terminal emulator with VIM and directly upload files to GitHub(so mostly just C code) ;)