1. You follow other people and get credits for each followed by.
2. You appear on Tweetbooster listings.
3. People follow you until you are run out of credits.

You get followers for free while your balance is positive. To keep your balance positive you need to follow other people. Of course, you can always buy extra credits if needed.

We cannot guarantee that your followers stay with you forever. However, you can refund your lost credits when somebody unfollows you! This is Tweetbooster's killer feature.