免费或廉价US电话

1. make calls from wifi:

https://www.truphone.com/us/solutions/ chose AppStore or GooglePlay then Install. Call and message other Truphone users free over Wi-Fi and 3G. Call around
the world for as little as 1p/1c per minute. Keep your existing phone.

2. Free calls vai GV

http://forum.mrmoneymustache.com/welcome-to-the-forum/free-wifi-phone-service-in-the-usa-google-voice-hangouts-and-hangouts-dialer/ 

2.1. Set up Google Voice and create a phone number, https://www.google.com/voice/ 
If you are viewing this on your phone, check the "Request desktop site" box in your browser, since the Google Voice workflow seems to work differently on phones and demands that you give it a real phone number. Click the gear icon for settings, then go to the Phones tab and follow the prompts to create a Google phone number.

2.2. Install the Hangouts Android application: This should come default on your phone, however you need to ensure that you have the latest version installed.
https://play.google.com/store/apps/details?id=com.google.android.talk&hl=en 

2.3. Install the Hangouts Dialer Android application： https://play.google.com/store/apps/details?id=com.google.android.apps.hangoutsdialer&hl=en 

2. 4. Configuration. On your phone, go to the Settings menu on the Hangouts application. Click your Google account (email address). In the Google Voice section, ensure that the "Ring Hangouts for incoming phone calls made to your Google Voice number" is checked. Go back to the first page of the Settings menu and click SMS.  Set the "Send SMS from" option to your Google voice number.
Now you can send and receive free calls and texts through the Hangouts application on your phone! How sweet is that?

2.5 More documentation: Voice calls through Hangouts:
https://support.google.com/hangouts/answer/6079055?hl=en  SMS through Hangouts:
https://support.google.com/hangouts/answer/3441321?hl=en 

3. Free Call via TruPhone (initial call from laptop/GoogleVoice to TruPhone)

Truphone works, but not well, and even worse with smartphones. for RECEIVING calls, you need to turn on call screening, and be able to answer the phone quickly to press 1. this is where a GSM flip phone is useful. The time required on either my android or iphone 4s is just not realistic.

To PLACE calls it works great, as long as you have a wifi connection and laptop....to make those calls FREE. i.e. initiate call from laptop/GV to ring truphone, truphone doesn't bill for incoming calls (as it is an international carrier, and most countries don't allow billing for incoming calls).

https://www.reddit.com/r/NoContract/comments/45hixt/truly_frugal_iphone_with_truphone_and_google/ 

Objective: pre-pay minutes that don't expire, work anywhere in the world, and to spend as little as possible.

Start with a full GV number ($0.00)

Add a used unlocked GSM phone (in this case, $75 for the original factory unlocked worldphone iPhone 4S)

Assume the majority of your time is in reach of a WiFi network you have access to. In the cellular settings, turn off ALL APPS except GV.

Next, go to Messages, turn OFF iMessages (otherwise it will send an intl SMS everytime you switch on/off

Next, go to Facetime, turn that shit off, otherwise IT will use data AND send an intl SMS to turn it on/off

Truphone is 9c min/SMS/MB BUT only charges for OUTGOING calls, texts, and data by the TOTAL MB.

Set your GV to forward JUST CALLS (not texts) to the Truphone. Now your incoming calls are free.

Now, how to make your OUTgoing calls for FREE? Initiate them using the GV app. If you're on WiFi, now all calls and texts are free (within the GV app, of course).

Outside of wifi range? To place a call is roughly 2KiB. to place or receive an SMS within the app is rougly 4KiB. so that;s roughly 200 calls or text messages for 9 CENTS. No matter where you are in the world.

here's my test log so far:

2/12/2016 11:04 PM 00:00:26 $0.00 Call received 2/12/2016 11:01 PM 00:01:23 $0.00 Call made 2/12/2016 10:59 PM 00:00:16 $0.09 Call made 2/12/2016 10:58 PM 00:00:20 $0.00 Call received 2/12/2016 10:57 PM 00:00:16 $0.00 Call received 2/12/2016 10:38 PM 00:00:21 $0.09 Call made 2/12/2016 10:35 PM 00:00:41 $0.00 Call received 2/12/2016 10:29 PM 00:00:37 $0.00 Call received 2/12/2016 10:15 PM 00:00:09 $0.00 Call received 2/12/2016 68.14 KB $0.01 Data used

so far it seems to be working great. will update if there are any hiccups.

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