Well, only you can answer "how much will I really be calling?". It is my observation that a lot of people are joined at the hip with their cell phones so you are only "missing something" if that applies to you.
After all, if you talk for 30 minutes on your Verizon roaming cell phone, you will pay $60.00 US which will buy you a cheap Ja. phone and 700 minutes of international credit to boot.
Yeah, if you are a "talker" then you are missing something.
Peace and Guidance