I have a prepaid phone so how does the upgrade work?

[XxShadowxX]

I recently got a text message from verizon saying:

Upgrade to a spartphone on June 6th and get one of our new plans starting at 60/mo for iltd Talk, Text & 2gb of data

So does that mean on june 6th I can upgrade to a different phone and get a smartphone that is still a prepaid one ..and how much does that usually cost. Ive never upgraded with a prepaid phone before. any ideas or has anyone done it before?