Build your own sous vide cooker

My girlfriend doesn't use YouTube a lot. Last week she asked me why do people really go on YouTube. I answered there was a lot of DIY stuff. People who want to cook, build things, repair stuff, test products, etc. Well here's a great example: you can build your own immersion cooker for around $75 (instead of 2000$) and this guy shows you how to do it, step by step, in this video.