There's a cheaper alternative, if you don't mind some manual setup:
- buy an ethernet -> phone adapter (Grandstream, Cisco, and Poly sell these) and a cheap analog phone.
- get an inexpensive VoIP number[0] and set up the phone adapter to log into the service you set up.
- set up a Google Voice[1] number if you haven't already. When you want to make an outgoing call, use the Google Voice app to initiate a call to your VoIP number[2] -- that way you're technically receiving the call there, so it's cheaper or free, depending on your plan.
[0] CallCentric has a $3/month plan that gives you free incoming calls and e911 service: https://www.callcentric.com/faq/46/529. This works well if you initiate outgoing calls via the Google Voice app.
[1] As of 2023, Google Voice doesn't work directly with Obitalk VoIP service anymore, or with any other VoIP devices :(
[2] if you need to let kids make outgoing calls via Google Voice unattended, set up the Google Voice app on an old iOS device in Guided Access mode and plug it in next to the analog phone. (But make sure they know to make 911 calls using the phone itself, not the GVoice app. I suggest printing a "Emergency: call 911 on this phone" label and putting it on the back of the handset.