Digikey has a pretty good web site for search, start with ARM M0+ and then select for what you want. I picked the 3x3MM QFN package as a selector and got a number of Kinesis parts, here is one that in 100 unit quantities is .50 each. In 10K I&#x27;m sure that is under 40 cents.
<a href="http:&#x2F;&#x2F;www.digikey.com&#x2F;product-detail&#x2F;en&#x2F;MKL03Z8VFG4&#x2F;MKL03Z8VFG4-ND&#x2F;4800183" rel="nofollow">http:&#x2F;&#x2F;www.digikey.com&#x2F;product-detail&#x2F;en&#x2F;MKL03Z8VFG4&#x2F;MKL03Z8...</a><p>This particular part 8K flash and 2K RAM. Now the M0+ is better for these low end parts because it has the Thumb instruction set which gives it better code density than the original M0