There's been a bit of discussion about TDCS here on LessWrong. If you don't know what TDCS is here's an article from Technology Review.
Here's a company (soon) selling a DIY kit to build your own.
tDCS is one of the coolest pieces of health/ self improvement technology available today. The US Army and DARPA both currently use tDCS devices to train snipers and drone pilots, and have recorded 2.5x increases in learning rates. This incredible phenomenon is achieved through a very simple device called a tDCS machine.
Today if you want to buy a tDCS machine it's nearly impossible to find one for less than $600, and you are typically required to have a prescription to order one. We wanted a simpler cheaper option. So we made one. Then, because we're all egalitarian like, we thought others might want one too.
The GoFlow β1 is a full kit of all the parts and plans you need to build your own tDCS device. $99 will get you one of the first β1's and will help us develop β2!
Here's a video from Journal of Visualized Experiments on how to administer TDCS.