Exhausted all the funds you've been able to raise? If your boosted post has done well, it should have driven a number of the people who saw it into clicking 'Like page'. What's your follower count now? It might be surprisingly high. They are now your "organic audience", and some of them (it all depends on Facebook's algorithms) will continue to see your non-boosted posts.
This means that you're now in a strong position to continue to publish, to reach supporters "organically", and to continue to grow your follower numbers if some of your supporters share some of your posts.
You can now use your page occasionally for action shout-outs, encouraging your followers to get more engaged in the movement. Don't forget to keep mixing it with news, comment and memes that will help keep up the passion and morale of our movement!