I have had OOMA since the first day when I gambled $399 on an unknown company and product for free long distance and a second line. One of my finest gambles

So when I heard about the mobile service, I signed up, and bought the app. I get the 250 minutes free as a "charter" OOMA subscriber, so my cost will probably be limited to that 9.99 of the app. I did try it - called my son on his cell phone, using just the built in mike and speakers and it worked fine. I don't plan on using it as my regular phone, but it could save me minutes in a pinch (I strictly use prepaid wireless) or be a backup. Guess I should invest in a headphone/mic - any suggestions for something small?
I am happy it is available as an option.