I like option 2. People with no money would not object to paying such a small fee ($0.25) and they would think that they could earn that amount anyway. Option 6 would probably work but it does feel a little artificial to me. Failing these, I'd go for advertising. Like somebody has already said, we have wall -to- wall advertising anyway in our daily lives, and steemit may need to use advertising (I voted for weekend-only advertising).