If you are looking to make an epic around the world trip, there are multi-continent open-jaw tickets that are available for sale.
Often these tickets will give you option of different cities to fly from and fairly flexible schedules.
Plus, the tickets are usually good for 6-months to a year, so you have lots of time to make the most of your ticket.
These tickets off you a lot of savings from purchasing several one-way tickets and to find a place that sells them you can just search for around the world tickets online.
If you're a student, there is a good chance your local student travel shop will have good discounts available for you.