One of my friends is head of social media for a clothing retailer. Their facebook page has over 250k followers. She said that they've experimented with paying for a few posts when they run sales, but the results didn't justify the added expense (it's much more expensive when you have a lot of followers), so they never pay to post anymore. If you're concerned about your reach on facebook, you need to interact with them in a way that doesn't only involve promoting your own page/product, so interact with your followers just like you would on your personal facebook page. Give them some exclusive material as a reward and also ask them to add your page to an interest list, so they are notified every time you post.