Straight talk promo codes are pretty rare. So I am always a little surprised to see them when they appear.
The Straight Talk 30 percent discount is working so far this month after being discontinued last month as detailed below. If you want to use it, do so sooner than later.
30% Off Phone Bundles Sitewide with code STRAIGHT30 at Straight Talk Valid 4/4-4/30
There appeared to be a temporary glitch in the March 2018 code, but it turns out to have been canceled for "vendor legal reasons". I'm not sure what that means, but it may have something to do with the fact that the Straight Talk brand is a collaboration betweeen America Movil (Tracfone's parent company) and Walmart. So this cancellation of this code may be related to that relationship.
They have had a few promo codes before, so I hope this gets sorted out eventually.
The fine print appears to say that it doesn't apply to iPhone purchases. I haven't tested it on everything they offer, but it seemed to work on all the other smartphones I checked.
Update 8/4/2013: No longer valid.