You just go to your WI-FI settings and connect to the mobile hot spot as if you were connecting to a wireless router.
Most places have free wi-fi, so you would hardly need to use your hotspot data then.
You also want to get a hotspot that has good 3G or 4G coverage.
You will not be using cellular data with the hotspot, you will be using the 3G or 4G, so be cautious, and use it in case of emergencies. You can also browse the web with it.
Personally, I just have a prepaid flip-phone for emergency calls, and I use my VOIP apps when I am near wi-fi. I only pay $15 a month for 300 minutes.
I will update this guide when I find an even better and/or cheaper method.
- A VOIP app
- A portable hotspot