In USA, Verizon has implemented pretty good LTE coverage in major cities. For their standard cell data plans, they do not charge a different rate for 3G and 4G

In USA, Verizon has implemented pretty good LTE coverage in major cities. For their standard cell data plans, they do not charge a different rate for 3G and 4G LTE. Unfortunately, they do try to charge 30$ / month for each device plus an additional 30$ / month if you want to do wifi tether/hotspot, so if you had a smartphone, a tablet and tethering enabled, you'd be paying 90$ per month just for cell data (not including calls, SMS etc.)