[just txt and calls mam]

I had searched but to no avail so will ask a few simple questions

I have a storn 9500 unlocked from the U.K. but am in the U.S. for 6 months.

The area I am in, South Dakota, See's verizon as the main supplier but they do not do sim phones but I need a sim for 6 months only for calls and txts

So my questions are ..what is a verizon world sim, will it work on my U.K. 9500 and what are the issues likely to be? Failing that anyone know another way of getting this to work?