Hi @lleak,
Welcome to the forum!
There is definitely limited functionality if you do not have the circuit boards. @mwood did a nice job answering a teacher with a similar concern in this post.
This page does covers budgeting for the circuit playground and the discounts available (near the bottom of the page). I pair students up in my classroom so I only needed one set.
I hope this helps but let us know if you have other questions,
~Michelle