I am from Germany, the origin of T-Mobile. In Germany T-Mobile is the carrier with the best data-speeds, the best coverage and *badumm-tss* the highest prices
I don't know the market-direction of the carriers in the US, but in Germany, they are going to the monthly based options which sounds a lot better than what u are talking about in the US.
that means you have NO COST in the first place (but u are paying 9 Cent for anything else then) 9 Cent for 1 minute calling, 9 Cent for 1 textmessage, 9 Cent for 1MB data.
BUT: you can make MONTHLY subscriptions like 10€ for 500MB data. 10€ for unlimited calls. 10€ for unlimited texts.
If u get over 500MB u'll get a text and if u answer to it with "more" u get another 500MB for 3€ or 10GB for 20€.
in that case for me I am paying 10€ for the data each month, needing no texts cause anyone here is on iMessage or whatsapp and i am not the calling person, so the 10 minutes or so per month will cost me like 90 Cents.
All this with the monthly option. Get vacation 1 month? unsubscribe the data and subscribe the international package. Bamm, no extra cost. U are the hardcore-caller, but use no data? Same thing: 10€ per month. U are a 80 year old grandma and just want a phone for emergencies? 0€ per month and that "hey I just fell out the bed, come pls help me up!"-call costs 0,09€.
ah, I forgot 2 things: calling to landline is always free, calling your buddy on the SAME carrier, too.
Can it be better?
edit: want a phone? 10€ to 20€ per month till it's paid off.