littleBits is behind many cool STEM kits. Its Gizmos & Gadgets Kit 2e is an invention kit that teaches your students science, technology, and engineering concepts. It comes with reusable Bits and 16 inventions for you to get started right out of the box.
Your inventions can be controlled using iOS and Android devices. Whether you want to build a crawling creature or rolling hoverboard, this kit works. Ships under $200 at this time.