Just put your kids outside. You don't need anything as a kid to start playing. We used sticks and mud and built ourselves houses and towns and had wars and put on plays and did everything under the sun without toys or anything.

Some trees and dirt will take you a long way providing thousands of hours of fun. As kids we found these big black horned beetles and started a beetle gladiator arena that kept us preoccupied for months at a time feeding and training our biggest beetles. Kids are very creative if you let them be.