1) I know so famous english daily papers like The Times, Daily Mail and The Daily Mirror. The Sunday Mirror is a weekly paper and it's a part of The Daily Mirror.
2) Regulary my father reads The Daily Mirror because it's very comfortable to read it. It's a tabloid and all of the news are short.
3) My family subscribes to The Daily Mirror and Th Times.
4) We're planning to subscribe to The Sunday Mirror to the next year.
5) Yes, of course.
6) I think these people try to save money or they don't have enough time to read newspapers every day and they buy single issues just to read only interesting news.