a) After communicating with a user from overseas, or another part of the country, the user will suggest that you meet face-to-face. However, they don't have enough money to cover the cost and will ask you to help out by paying the whole, or half the amount of the travel costs or hotel costs. Sometimes they will even suggest you meet mid-way to reduce the cost for each person.
b) Some scammers will even send you scanned examples of faked tickets, to prove they are supposedly genuine, however at the last minute an extra cost or emergency will occur. They will request you pay this for them so they do not have to cancel the meeting.