I was keeping eyes open, too. I don't need another Mint line, but another $20 cashback offer would have let me extend my Mint access date by 45 days...... at roughly $14 to do so (with $10 cashback), I decided I'd be smarter to put the money towards a line that was sustainable at around $10/mo.
I'm going to have a little fun with the Mint plan this weekend-- a road trip to an area that has marginal coverage from everyone except U.S. Cellular. We're taking Mint (T-Mo), FreedomPop (AT&T), Tracfone (VZW), and Sprint, and seeing which works. I probably won't be able to prowl the countryside looking for dead spots, though.
I got an email from Mint letting me know about the upcoming data increase on their plans. It included this:
"What does this mean for you?
After January 29th, your current plan will automatically go from 5GB to 8GB on it's next monthly reset at NO charge."