It all depends how you sign up. If you buy the device up-front and don't enter a 2 year contract, you'll pay a $35 activation fee but you can cancel anytime you want.

They have the terms posted on their website http://www.clear.com

Their coverage maps are also quite detailed, and they even show where the towers are located. Definitely check that out before purchasing.

The Clear Spot 4G worked great in MSP Concourse F this morning!