Public transport is cheaper, but also less comfortable. In big cities underground (subway) have been built. They are the fastest means of transportation and the underground trains usually go every five minutes on average.
For some people travelling is very expensive. Young people like hitchhiking or just hiking especially.
When going abroad we must get necessary documents. First of all a valid passport and visa to some countries which we can get at an embassy. We must change money in a bank or exchange-office. We should know foreign languages.