Surprisingly, there are quite a few prepaid data plans from major carriers in the US. For example, I'm using T-Mobile's 4G Monthly plan which provides me with

Surprisingly, there are quite a few prepaid data plans from major carriers in the US. For example, I'm using T-Mobile's 4G Monthly plan which provides me with 5GB of data for $30 a month, no contract. You can actually get a nano sim from T-Mobile, all you need is the IMEI number from the sim in order to register for their 4G prepaid plan. There are other carriers too, like boostmobile, cricket, virgin, etc.