I told the students that they would each need to complete the task cards/Bunny Bucks individually, but the materials that they earned belonged to the group. Once they had earned their supplies, as a group they could then begin building their tower. I wanted to make sure that the students understood the content first, but also that their individual work contributed to the success of the whole group.
We started with the clothespin Bunny Bucks (I did each set of cards on a different color paper to help the students quickly know which material cards they still needed to complete) and then the popsicle stick Bunny Bucks, and finally the bunny Bunny Bucks. The students did AMAZING with managing their time and resources. I asked them to turn in each set of cards and collect their resources before moving on to the next set of cards. It worked out really well and the students did a great job of coaching one another when they were having some struggles instead of just sharing the answer with their neighbor (we reviewed this first!).