I bought a T/Bolt and took it to a verizon store they gave me a sim card free.
If you already have a 4G SIM card with VZW provisioned (activated) then simply insert it.
If you already have a 4G SIM card UNPROVISIONED (un-activated) it can be acitvated online to a existing VZW phone # profile if you already have VZW service on vzw.com.
If you don't go to a VZW store, pick a plan the will activate and insert and boot.
If online they will ship you one...