Actually, you can do something. You can run a tor node (from your home mostly for free). You can also set up a bridge in 10 minutes via https://cloud.torproject.org/ for just $3 per month.

You might not directly see the good that you do, but you would be doing a significant amount of good! That tor node will push a lot of freedom bytes, and that bridge will help circumvent Iranian, Syrian and Chinese censorship.