Millenicom has a "Hotspot" plan that provides 20 Gbytes of 4G service on the Verizon network with no contract. However, there are device purchase and set-up fees. (Millenicom is a Verizon reseller.)
The Novatel MiFi device is identical to the one sold by Verizon (ours had an Avery label on it that said "Millenicom", that, when peeled off, revealed a Verizon logo underneath); and Verizon has the best nationwide coverage.
Cost is $69.99 per month with absolutely no additional monthly charges, and you can cancel at anytime. However, there is no provision for going over 20 Gbytes per month. The first time or two, they cut you off at 20 Gbytes. If you continue exceeding the limit after being warned, they cancel your device.
There is also an "Unlimited Plan" for $79.99 per month, but it throttles you at 50 Gbytes. Also, it is on the Sprint network, which does not have as good a coverage as Verizon.
We have been very satisfied with the Hotspot plan and have been a Millenicom customer for about 18 months.
Plans | Millenicom
Note: The Novatel MiFi device has a connector for an external antenna. We purchased an amplifier and external antenna in a kit purchased from MaximumSignal.net. You can also purchase several antennas separately (without the amplifier).
Maximum Signal :: Cyfre Direct Connect Amplifiers :: Peak Reception "Rockies" Extreme Dual Band Amplifier + Mobile Accessory Kit