1.Yes, they do.
(Traveling is very popular among students in Britain)

2.Hitchhiking is the cheapest ways to travel. It isn't a good way to travel.
(The cheapest ways to travel is hitchhiking, but it isn't reliable and it can be dangerous)

3.Bucket shops are the shops which sell cheap airline tickets to countries like the USA, Thailand and Australia.
(There are a lot of shops (called "bucket shops") which sell...Australia)

4.They are not very comfortable because you have to share the cooking but special because it is a cheap way to see parts of the world that most tourists never go.

(It isn't very comfortable and you have to share... tourists never go)

5.We can usually recognize them because they often paint a kangaroo symbol somewhere on the van.
(You can usually them.....somewhere on the van)