My wife and I are going to FIRE this summer and spend several years traveling all around the world. We are planning to cancel our cell phone plans here in the USA. We are trying to figure out a free way we can send texts and make phone calls over wifi, and want to have a phone number that we can use as our contact number for banks, credit cards, financial institutions, etc. I am looking for advice on the best way to do this. I've been trying to research Google Voice, Google Hangouts, Whatsapp, Skype, etc. but I can't figure out what is best for what we need. Thanks for any advice you can give.