I was interested in this so I thought I'd share info in case anyone else was interested. I'm brand new to the forum so if this topic has been covered already I apologize in advance.
I'm currently running an ATT Go Phone standard prepaid sim in my Passport. I got the sim kit from Walgreens.
Phone specs: Black, unlocked from factory, 10.3.2.2226 software, SQW100-1 model.
Go phone plan: unlimited talk and text, 4.5gb data, 4G LTE
$60 / month
As far as smartphones go, I've owned 2 iphones, 2 android phones, and the Passport is my second Blackberry phone. I only went away from 'Berry a couple years ago because there were some apps that I wanted to use but they didn't work on Blackberry. Now that Blackberry can run many Android apps I'm back in the game.