IPhone 5 payment on T-Mobile?

The T-Mobile simple choice plan says that it is $50 a month but then it says that unlimited 4g data is $21 a month and that the monthly payment is $20 monthly. Does this mean that I have to pay $91 per month? Please simplify this for me!

Giffgaff is the best don't go on t mobile or orange

Simple choice is talk and text… Bam. $50

and since this is a smartphone, you are mandated to get a data plan… Bam… $21

and since tmobile no longer has contracts anymore, they operate like a used car dealership… Pay a down payment, get the car, and every month you make a payment… Or loose the car! In Tmobile now, you make a down payment on the phone, and your monthly payment is $20/mo until you reach 2 yrs… Lol lol lol… So… Bam… $20

50+21+20 = $91 subtotal… Plus average federal state county city village tax fee surcharges your local government imposed onto all wireless carriers in yoru area… 13%… On average… So thats about a $100-$115 per month bill… Give or take $5-$10 depending on your tax rates…