Unfamiliar with traveling outside USA.  What is best/cheapest/easiest to use brand and plan cell phone for calls and text?  Can it be purchased prior to traveling?

I would recommend you use Google phone which is completely free. You can set up your account before leaving the US, because they confirm that you are in the US, once you are out of the country you can log in to your account and can make calls from your computer. The calls in the US are free, sound great, and there are no glitches.

I know your question was asked a while ago but this might help anyone else who comes across this post.