Everything you need apart from 4 x AA batteries.
An important note about the price: We have paid for all the parts upfront, tested, stored, soldered, programmed, drilled, cut, glued and kitted them. This takes time to do and staff need paying. If you want a pre-prepared, tested kit, then you are in the right place. If you want to pay the lowest possible price, you can see the parts list here so you can purchase them yourself.