Here is a kit that gets you started with brain activity reading wearables. The Ultracortex EEG Headset Kit is an open source, 3D printable headset that offers you research-grade EEG data. The Ultracortex Mark 3 is capable of sampling up to 16 channels of EEG. This particular kit comes with electrodes, 3D printed frame, and other parts you need to get started.
The Ultracortex headset is great for students and researchers. More information is available here.