"Cheap" temp measure solution

I would like to install few temperature sensors at home, they should be battery operated, but if the most viable solution is without battery, then fine.
I have Z-Wave and Zigbee available (via Hue and Hubitat, I would rather prefer Hue anyhow).

Any idea/hints?

I think the Shelly H&T will be the cheapest. They're Wifi.

And can I integrate them into Indigo with Shelly plug-in?

I've got a bunch of Aeotec SmartSensors around my home. I operate almost all of them plugged in but the do have a battery option. I like this sensor because it reports more than just temperature. It also does motion, light and humidity. So I can use them to trigger various actions around the house. An added bonus is that since they are z-wave the help reliability of the network by extending z-wave commands.

And can I integrate them into Indigo with Shelly plug-in?

Yes

I've got a bunch of Aeotec SmartSensors around my home. I operate almost all of them plugged in but the do have a battery option. I like this sensor because it reports more than just temperature. It also does motion, light and humidity. So I can use them to trigger various actions around the house. An added bonus is that since they are z-wave the help reliability of the network by extending z-wave commands.

They are good, but definitely not cheap.

I’ve got a few Vemmio Z-Wave Plus temperature and humidity sensors. They’re £19 on eBay.