Actually I HAVE seen it. The $50 includes unlimited minutes and texting. which are in fact a $40 value. Funny you post a link and you FAIL at reading the info. Take a look at the pic I posted. See where the minutes and texting are INCLUDED with the data? Also if you go to your link you will see the data pricing for just a tablet to just a Mi-fi and no calling or texting is $40 cheaper for the same amount of data. Thus minutes/texting is worth $40. So if Unlimited minutes/texting and 1 GB is $50 and minutes/texting is $40 the 1 GB data is actually $10.
Actually the $50 is covering mainly data for the several phones. It is the per phone charge that is a majority of the unlimited talk and text part. Hence when you add a second phone you don'g get more data, you have to get an upgraded tier to do that.