I get 120GB a month 'fair use' on my 20 euro a month plan here in Ireland. If I exceed that, my speed is slowed down, but internet continues to work. In other words, its not something I need to think about. These kinds of plans seem to be ubiquitous everywhere in the world now - with the exception of the USA, Canada and Australia / New Zealand.
I get 150GB for €8 in Italy but my ISP is trying to convince me to move to 200GB/€10.