Yeah, I had to go and ask at Millenicom if there was an actual limit to the "unlimited". I guess they don't want people using Netflix. LOL.
Although quite frankly I'm capped at 475Mb per rolling 24 hour period for $80 a month with Hughesnet-- but that goes quickly because the modem software miscalculates and claims I load 10x what I'm actually loading. Plus it often times out so I have to reload things over and over. Internet goes out completely when it rains, is cloudy, windy or just randomly for no apparent reason. I'm so accustomed to not being able to download much that I can't imagine using an entire 50Gb. That would be a hell of a lot of porn. :P
To the OP, if your ESN on your air card/modem is clear you can probably get the BYOD plan with Millenicom so you won't have to purchase a new modem. That would save you the $99 plus $15 shipping fee.
There will still be about a $50 activation fee plus the $69.99 per month for the service.