has a $10/month plan (paid yearly) that gives you a real US phone number that can accept texts from any financial institution (as well as make/receive calls, but that's expensive) It can be activated in Thailand. I had my starter sim card shipped to Thailand from Amazon. I also use it when I go back to visit the US which makes it convenient for me.
If you should ever decide to marry in Thailand, or to register an existing marriage. I'm not sure when else they might be required, but doing it while still in the states is pretty easy, but if you're not there, it's very difficult, even if you travel back for vacation, as it can take a long time to do.
Get your birth certificate and marriage certificate (if married) authenticated *before* leaving the US, otherwise it will be a very difficult process, and Thailand requires authenticated documents: