Jonsey, if you don't have it now you might want to consider getting the share plan. Unlimited minutes, unlimited text and 2 gigs of data. If she has a smart phone, the 2 gigs of data is probaly already attached, it might be mandatory for the smart phones.
I use the email feature daily, send and receive pics and have an Ipad linked to the same system and I have yet to use 1 gig of data in a month.
What I do not do is watch football, movies and other activities that require data downloads. Occasionally I do download a utube video but usually reserve that activity for the computer.