There are many possible ways to reward the person who play an important role in Knowledge playground.
1. Real Money: part-time job, Salary, weekly wage or just reward.
2. Special Money: They can create their own money which can only use in their group/town/society.
3. Chips or Coupon: They can also give the chips/coupon for special usage.
4. Etc. Product: If the host of the Knowledge playground is a farmer or producer of something, they also can reward the helping persons by giving their products. An Artist Knowledge playground can also provide the material and the person who join his space can take their master piece home