Tindie.com -  Buy direct from the creators and make something amazing.
Tindie is the marketplace for DIY hardware. You can find open source and small-batch electronics to build projects that demonstrate STEM principals, or source kits for hands-on classroom activities. If you've developed STEM kits with lesson plans, you can also sell them on Tindie. Got questions? Email hello@tindie.com—we're always happy to help.