If you would like to complete the material covered in this camp on your own, there are a few different kits that you can purchase based on how much you can spend. The Arduino platform is an open-source hardware and software microcontroller environment geared towards hobbyists, makers, and engineers alike! Due to its open source nature, anyone can manufacture the boards. There are many different options as a result.
There are many more options out there. I just wanted to outline a few for you. If you purchase one of the non-Arduino kits and you can, consider contributing to them for creating this great platform: https://www.arduino.cc/en/donate/.
If you would like to run this camp, here are the materials I purchased for a 24-person, one-week camp. As noted above, there are many other different versions of Arduino kits that can be purchased to adjust the budget. You may also find that you don't need some of the additional components listed or you may need more! Adafruit and Sparkfun are two great companies that sell many different electronic components that are perfect for this environment. Try to support the little folks as much as possible!
Camp Purchasing Sheet: https://docs.google.com/spreadsheets/d/1gB46eG4wxMwlYKQ9xe-OkRq8bpji0dAKNFEI0Cj4WR0