Saw this over on HoFo. For those free-plan sims bought from Bestbuy, Freedompop is charging an extra ten bucks for activation now. Seems like a lot of people are getting charged $10.99 to activate, instead of the old 99 cents. Dang!
$10.99 looks like the $.99 activation plus the $10 deposit... so they closed the loophole?
Didn't know there was a $10 deposit. I have a couple that I picked up in January that I didn't get around to activating. What's the $10 deposit for?
It's frequently hard to figure out whether FreedomPop has changed something on purpose, or if it's a glitch.
This seems to have been going on for several months, where some users are stuck with a $10 charge, and others are not. Maybe everyone is getting hit with it now.
And of course it's difficult to get a clear and precise answer from the FP reps on any forum. Universal changes are typically found to exist in an updated TOS after being run into by users. (Updated prior to or on the effective change date, but not really announced anywhere....)
I ran into this problem ($10 charge) back in January with a SIM purchased from Target, and so did als.
https://www.nthcircle.com/forum/freedompop/1247-freedompop-lte-sim-1-at-target-ends-today-1-6?start=10#20333
but it was working fine without the upcharge for most folks then, and it appeared to me that a FP rep on Slickdeals confirmed that the $10 charge should have been entirely optional for those SIMs. Since I was only attempting the activation as a learning exercise, I quit trying and didn't follow up. I don't know whether the issue was temporary at that time, or if it had to do with some SIMs being mis-categorized by FreedomPop, etc.
The $10 deposit seems to be the "fee"/deposit for dowgrading from the free trial plan to a basic free account. Screenshots in this thread:
In theory, this charge should not be a requirement for the 3rd-party SIMs, since they don't include the 'free trial' to downgrade from......unless of course, there's been a TOS or policy change that makes this something other than the downgrade fee it started as.
I don't have any FP SIMs or phones using their service, so I have never experienced any "phantom" billing problems. But posts like these from @KentE, @peterquinn, and @PEW seem to highlight the ongoing transparency problem that FP has. One never knows exactly what terms and conditions are applicable, and when they take/took effect, thus one never knows when a new, undisclosed fee will be assessed for their "free" service.
If, and when, they ever make everything clear, transparent, and consistent, I would like to give their service a try; until then, good luck to all of you who are brave enough to venture into FreemiumLand! 
Users are definitely dependent on 'crowd-sourced' knowledge of how things work at FreedomPop, and a prediction of costs. Transparency is a problem, but finding information is not hard for those already schooled in user forums. As noted here, sometimes group knowledge lags behind policy changes........
(And by the way, PEW is a great source for FP knowledge.)
I have over 20 "freedompop friends" that stay in touch, and billing problems are rare if one is willing to do due diligence and follow the 'group knowledge' tutorials when setting up an account.
Customer Service is slow, and the process can be arcane-- but usually effective as long as you don't have a real technical issue or a confusing account issue. (In which case, you're probably better cutting your losses and starting over unless you're as determined and stubborn as many 'frugal' people are.)
As a tip you can get decent freedompop customer support via facebook chat.
Thanks for the explanation / clarification, @KentE! Glad FP is a great fit for you. I guess I'm just inertia personified, happy with my reasonably-priced Twigby service, which to date has been completely trouble-free and surprise-free, billing wise.