Can anybody suggest any good but cheap sensors (preferable RFXCom or Z-Wave) for temperature, wind, humidity, etc ... I looked around, but can't find the "cheap" ones

I am still Dutch
Preferable also to be able to use multiple of the same type, not limited to 1 or 2 channels.
DomotiGa / Z-Wave / RFXCom / Visonic PowerMaster / Home Assistant / Zigbee2MQTT / DSMR Reader / Toon1 (rooted)