The first “do it yourself” EEG biofeedback machine that I found online was called Play Attention. They call it “edufeedback” actually.
They hide their prices on their website, but after calling them I was quoted $1795 for a 2-user home version or $2495 for an unlimited user professional version.
Their website is playattention.com.
From what I understand, the Play Attention system consists of a bicycle helmet lined with sensors and an interface box. The interface box hooks up to your computer. You put on the helmet and play very simple video games using your brainwaves.
One of the video games involves steering a race car by concentrating. But their website was extremely vague about what types of video games are actually included.
They recommend using Play Attention twice a week, 30-40 minutes per session. After 40 to 60 hours of use, they say your concentration will be improved for the long term.
It sounds good but I think there are many cheaper machines out there that may be better. I will list some other ones soon.