I have been receiving feedback that I can use eBay suppliers to lower my price on the MAX7219. I had previously considered that option, but after some research I have found that a lot of people are receiving counterfeits on eBay. While some counterfeits may work, their reliability is questionable and that would make my product unreliable.
Make a robot friend with Adafruit’s CRICKIT – A Creative Robotics & Interactive Construction Kit. It’s an add-on to our popular Circuit Playground Express, FEATHER and other platforms to make and program robots with CircuitPython, MakeCode, and Arduino. Start controlling motors, servos, solenoids. You also get signal pins, capacitive touch sensors, a NeoPixel driver and amplified speaker output. It complements & extends your boards so you can still use all the goodies on the microcontroller, now you have a robotics playground as well.