There are some alternatives, but they may not be all that much cheaper. Sprint has the overdrive hotspot (for use with a plan wifi), but it is $59 a month.
I am switching from comcast to Clear. Under comcast I had 12 MB per second (actual) for $43, but I am going with Clear which is a wireless provider. My home network drops down to 4MB (so far, I am going to move it around to see if I can get up to the 6 advertised) and a hotspot that is supposed to be 3 MB. The hotspot is still on its way so I cannot test it yet. But the total for Clear is $55 a month. (both before taxes.) So I have convinced myself I am only paying $13 for unlimited.