@aogorman - if you already have a 433 MHz bridge they are good value at $9 US + delivery. Last for ages on battery, less false positives than the Genio, but that may be because of how I have the Genio configured.
Don’t buy the Sonoff reed switches, they only have open notification not open/closed. I use the GS-WDS07 because you can pull them apart and do cool things:
Only issue with 433 MHz is that building penetration compared to wifi is not as good, mainly due to lower transmit power. This however translates to longer battery life.