It's a shame that the Amazon Fire phone was such a bust. It had some nice features, such as the rather incredible 3D lock screen that rotates cute movable images. That aside, when I saw that this $600 phone was available on ebay for $150 that included (!) a Prime renewal (it extends your existing Prime subscription) AND came with an unlocking code, I realized this is a tremendous bargain.
This is a phone that runs on the AT&T GSM network using an easily accessible SIM card. In other words you can swap out the AT&T card and replace it with any other SIM card that runs on a GSM network, the one used all over Europe. So I could get a phone to use in Europe and get a pay-as-you-go phone network in the States such as T-Mobile, EZKonnect, Tracfone, etc. AND I would have a great media player that used the Amazon app system (not as good as the Google Play store, but since I have tons of Kindle books and love the Amazon ecosystem, no problem.)
I ordered one, got a T-Mobile SIM card ($3/month access and a new phone # that I won't need or use, but could if I wanted to and it could Skype or use some other VoiP), unlocked the phone (ridiculously simple), and logged in to my Amazon account and connected to my WiFi network. Bingo, I have a great reader, phone, and media player for a total of about $30. Since it works on WiFi you need never use cellular data plans unless you want to.
There appear to be lots more of these available on ebay.