I've been looking at this for a small robot-club session, not a purchase request yet:

https://pollen-robotics.com/microduck/

I want each person to have something to investigate while someone else has the hardware. My rough idea is comparing a simple behaviour in simulation with what happens on a clear indoor surface, keeping the tests supervised. No promise that the robot will arrive for a particular session.

What would you split between four beginners? I'd rather finish with one modest thing we can explain than four copied demos. Also interested in reasons this is the wrong platform for that plan.