Anybody Used the Data Plan for...

Hello-

I am wanting to use the mobile hotspot. For my carrier there are 2 different plans, one for just the data used by the iPhone and one for the Data used for the phone and for the mobile hotspot. If anybody has used this type of Data Plan for the phone and the mobile hotspot has that worked out? How do you know when you are nearing the limit of your plan? Is there an App for this or does the carrier have the ability to notify you if you set that up?

I live in a bad area where my option for an internet connection is really bad and this area will not allow other companies to put in their internet. I am trying to finish my doctorate degree and some of the current work is online but I can't even stay online to complete what I need to do. I would go to a wi fi area, but I need to be gone nearly all day for these assignments so I was thinking about using the mobile hotspot on the iPhone as my internet connection. I doubt I use much but I would need to somehow keep track of the usage.

Just wondering how it has worked out for people who have used their plan for their mobile hotspot on their iPhone.