T-Mobile filters by IMEI. The Nexus 7 (both the 2012 & the 2013 models) are recognized as mobile broadband devices, so they will only work with an appropriate data plan.
Adding an MBB line onto a postpaid T-Mobile account is fairly cheap. It's $10 for a basic 500 MB data plan, and you can add more data for $10 / 2 GB all the way up to 12.5 GB total.
The 12.5 GB plan isn't listed on the website, but it's definitely available. Another off sheet plan is an on-demand data plan. The plan costs $10 / month, but when you already have a voice line you get a $10 discount on it making it free. There is no data included in this plan, but you can buy "data passes" for $10 which gives you 1 GB of data that's good for a week, or until it's used up, whichever comes first. It's a good plan for someone who only very rarely needs the embedded data and doesn't want to pay for an unused plan every month.
Posted via Android Central App