Net 10 (AT&T MVNO)
$50 a month no contract for unlimited talk, text & data (although realistically no such thing as unlimited data anymore as they now cut it to 1.5 GB due to AT&T)
Customer service is crappy like one would expect but the trick with them is to bypass the official customer service number & call corporate who answers & is pretty much all people from the US.
Actual service is great since it is using AT&T's network. I switched over to Net10 after using T-Mobile on my iPhone. I had no complaints about their service but I did not like being limited to Edge (2G) service when not on Wi-Fi. Now I get to use 4G on my phone by being on AT&T's network.