The possibilities to do activities without draining your money are only limited by your children's imagination. I am sure from experience you know they have quite the imagination! Listen to your kid's ideas and try to put it into practice it in the near future.

Consider their ideas and actually do them. They might suggest fun and free activities all by themselves in the future. If you can create a reward for their creativity, not only will it fuel their creative potential throughout their life, but you will be establishing a healthy habit for them.