Thanks for the examples and your comments.
A couple of comments and questions to expand in the topics:
1- the unlimited data plans started with EDGE and 3G, right? The carriers practice of keeping you under a contract by renewing it drove us up to LTE. For EDGE we were paying $20/month, then for 3G they bumped the price to $30/month.
What are the max. amounts of data that can be downloaded at those speeds?
2- It is my impression based on what I have seen over the years in other threads that the US carriers plans are a better deal when compared to other countries except others in Europe and Asia. They are use to overcharge us, similarly to cable operators and home ISP.
3- It is 2013, and we are almost in 2014, the amount of data should not be considered such as big, the data hog paradigm should be obsolete. Back in the 80s a modem connection of 300bps was the standard and a 3.5" floppy with 800K was enough to boot your Mac and do some quality stuff. There were no data cellphones. Over time things evolve to bigger faster better and should be lower cost (this have not changed much).
4- HD video is evolving into UHD and 4K, Retina Displays and so forth are already here. But the big size of the market is still texting and tweeting and updating Facebook status, and doing simple things that even when they are paying for 2GB of data they are not fully using them, and the carrier doesn't give you a roll over service: it is use it or loose it, but if you use a little bit more than your quota you pay a bigger price.
5- Roaming charges are ridiculous. Hopefully T-Mobile move could help to adjust that market.