The board in question can be found between $2 and $3. Once you’re at the point of wanting to build "an electronic thing to notify you of something", the actuall

The board in question can be found between $2 and $3. Once you’re at the point of wanting to build "an electronic thing to notify you of something", the actually cost difference in the BOM between the simple approach and the “IoT” approach is basically zero. EDIT: Sorry, not the exact board, but something that’s basically the same. The usual “value adds” you find on top of the basic wifi board are 1. on-board usb/ttl chip and 2. 5v-3.3v regulator. Still, you can find something with both of those for under $4.