I'd say look into the MiFi2200 model,using either the verizon or virgin mobile service plans.
I have the virgin model,and I use it during moments where I dont have accessible wifi.
The verizon model is a bit cheaper (60 bucks i think) but the plans may be more expensive.
I bought the virgin mobile device for about 150,and the unlimited data plan is about $40 bucks a month.
You can pick up the virgin device at bestbuy,and the verizon one at their carriers.The service is good,and it connects with everything.I can even use it to connect to xbox live.