I provide all these apps for free. While I’ve been able to cover development costs out of pocket, there are ongoing costs for hosting and promoting, and future costs to translate these apps for other countries to benefit from critical thinking curriculum. Also I speak at teaching conventions about curriculum reform, so there are travel costs. Your donation will be used for costs only, not personal income. Note that this is not incorporated as a 501c3.
Or to send a check, email me to get my mailing address.