Is there an android app to call 1800 numbers in USA and Canada and other US numbers for free?
try to use CallsFreeCalls app. It's refreshed now.
You can use Skype for unlimited calls to the US and Canada, and it's only $30 a year. Just buy the North American plan. But as for free, I don't think there's a solution.
Try Groove IP. You can read about its features etc here:
there is a skype plugin if you plan to use desktop app. Otherwise skype for android allows you to call for selected free numbers
Tmobile has an app called the Bobsled app that is free to anyone on any carrier with an android phone. It allows you to make free internet phone calls to anywhere in the US whether it is lan line or mobile. It does not use your minutes as it is an internet phone. I use it any time I am going to call doctors offices, companies, etc. The call quality is very good. You can also do free video conferencing and texting to other bobsled app user not matter what company they go through. The best part is it is all free.
Tmobile decided they would rather lose a few cents on cell bills if they can cost the other cell phone providers dollars!
You can install Skype for Android free from https://play.google.com/store/apps/details?id=com.skype.raider&feature=nav_result#?t=W251bGwsMSwxLDMsImNvbS5za3lwZS5yYWlkZXIiXQ.. . The free numbers supported by Skype are mentioned here : https://support.skype.com/en/faq/FA24/how-do-i-dial-toll-free-numbers-for-example-1-800-1-866-and-1-877-number-series .. I do not think there is any android app to call a paid number free however lot of free VOIP apps available including Skype where if the other side also has the same VOIP app, you can make free VOIP call over your internet.
There is also a very interesting Android app called HeyTell : https://play.google.com/store/apps/details?id=com.heytell&feature=search_result#?t=W251bGwsMSwxLDEsImNvbS5oZXl0ZWxsIl0. . Check it out, it is like walkie talkie over internet across geographical location in real time.