Necessary expenses to travel to and from Mexico

I would like to know what are the best ways, including convenience and cost, to pay for the tax when tourists leave Mexico and using one's smart phone while in Mexico.

I visited the www.visitax.gob.mx site and I'm assuming that's the official website where one can prepay the tax instead of taking care of this at the airport. Is this how most American tourists pay this tax?

The breezesim.com is what I found to allow one to continue to use their smartphone in Mexico. It will be $8.25 for 2GB of data for up to 15 days. I have not completed the transaction yet since I have plenty of time. What are other/better options that tourists use?

I already set up our round trip shuttle ride from the airport to the hotel, so we're good there.

I would appreciate any other pertinent information that'll make our first visit to Mexico as a family. Exchange currency at a local bank? I never use airports since their rates are always higher. Is this even necessary at all?

Thanks in advance.