walmart, i got a StraightTalk (uses Verizon towers) hotspot for about $60. i think it came with some data, but you can pretty easily reload online. I also have a Tmobile phone that can be used as a hotspot, so I have pretty good coverage between the two services. If you have a smartphone, most of them can be used as a wifi hotspot, provided you pay for that service.
AT&T, Verizon, whatever provider you want, purchase a wifi hotspot box, buy whatever level of data you want. turn it on, and go. Works about anywhere you have sell service with that provider. You can go to Walmart and buy all of it.