tutorial and a 326 page PDF Users Guide (download PDF) (view online) for an unannounced NET10 branded Samsung Galaxy S4.
The tutorial calls the phone the Samsung SGH-S970G, a name that doesn't give much away. But the manual positively identifies it as a "Samsung Galaxy S4 4G LTE Smartphone", model S970G. With TracFone, NET10 and Straight Talk phones, a G suffix on the model number indicates a GSM phone. All of the NET10 and Straight Talk GSM Android phones to date have used the AT&T network so it's a safe bet that this one does too.
The tutorial and manual are strong evidence that the S4 will show up on NET10 and probably Straight Talk some day, although occasionally a tutorial is posted for a phone that never reaches the market. We don't know the release date or price, but NET10 and Straight Talk phones usually aren't discounted much, if at all from what comparable phones cost on the open market. The 16 GB S4 for AT&T is available for $649 on Ebay or $679 from Amazon, so I expect the NET10 version to be between $650 and $700 if and when it arrives.
Update 11/12/2013: The Samsung Galaxy S4 is now available on the Straight Talk site priced at $599.99. Surprisingly it's only available in T-Mobile (GSM5) markets not in AT&T ones which is either a mistake or else the phone is on T-Mobile rather than AT&T as originally expected.
Personally, I don't see the point of buying a phone from one of the Tracfone companies if the same phone is available anywhere else. Straight Talk and NET10 Android phones are invariably locked down and crippled so that they won't accept manufacturer's updates. If the NET10 S4 comes with JellyBean, it will never see an upgrade to Kit Kat, for example. If you want an S4 on NET10, buy the AT&T version from any reputable seller and put a NET10 AT&T SIM in it. That way you will have a phone that gets timely updates and will have better resale value than the crippled version from NET10.
Source DeviceAnywhere via HowardForums