The cost of the Internet depends on the country in which you are located. The richer the country the higher the cost. I was in a country where unlimited Internet costs less than 2 dollars a month. In the USA the same online is 70-100 dollars. If there is such a difference in price I'm sure the price is fictional and it can be adjusted in any direction.
Wrong. The higher the demand for internet is, the higher the price will be. Also it depends on the number of internet service providers available on a certain country. For example, here in my country, there are only two ISPs available, some other ISPs (which are significantly smaller) only rent the infrastructures of the two established ISPs, resulting in to an even expensive ISP option. Add to that fact the number of users who really need internet for their work, and you'll have two greedy ISPs that'll bill you to the bones. Mobile data could be an option for running bitcoin, but over time it will be more expensive compared to having a wired internet setup.
Sending and receiving bitcoins or altcoins doesn't really use that much bandwidth. Even mining doesn't, and my 2GB mobile plan a month still has a 500MB excess for a month-long operation. Right now, using bitcoin is only a personal choice, and we got a long road ahead before it becomes a necessity.