I have read that alot of users' workflows involve C4D and Arnold or Octane. I have Apprentice and an Indie license, and have read that people save an alembic file from Houdini to use in C4D, but I can't seem to save one from my Apprentice or Indie versions. Is it possible with these, or do I have to commit to an annual license? Is there another way to work between the programs than saving an alembic?

Alembic export is not supported using Apprentice. You can read Alembics, you can't write them.
Also be aware than any file you create using Apprentice remains a non-commercial license. So if you open a .hipnc file in Indie, you still won't be able to export an Alembic.

If you have an Indie license, get rid of Apprentice immediately, you won't need it anymore.

Hmm, I'm still having trouble with exporting alembic in Indie. The only option I see is FBX, alembic is there but I can't choose it… Any advice appreciated!