Here are some affordable options for continued learning and play at home. These are not the LEGO Robotics kits that we use at the Treehouse, but I have personally tested these out and the quality is good and the prices are low.
Below are the same Circuit Cube kits that we use in some of our classes. These are not LEGO products, but this system is great for combining with all of the LEGO blocks that you have around your house! Unique circuitry system and a fantastic app that runs on iOS, Android and Chrome.
Here are the LEGO Robotics kits that we use, we only recommend these large purchases if you believe that they will get used for large amounts of time!