Be careful picking out your sim, it might not have telephone capability.

Arrived at the airport and grabbed a SIM for 150k with 3GB of data ("unlimited" but even the throttled speed is pretty speedy in Vietnam). Didn't think too much of it, was in a hurry,so didn't look around for price.

Flash forward a week, and I'm trying to get a Grab-Taxi (like Uber) back at the airport after dropping off a friend. Four guys canceled on me. Turns out the SIM I bought was data-only. My guess is they called me, the phone didn't answer, and they canceled.

Another 30k ($1.50) would have gotten me the phone. So now I need a new SIM, gonna stick this one into my tablet.

Grab/Uber are the way to get around now (unless you ride a bike), so make sure your SIM has phone.

On the plus side, I'm gonna refer myself with Grab and Uber to my new number and it should probably pay off the new SIM card with free rides