Are you planning to go back to where you started from? If you're unsure of the date on which you'd like to travel home, you can ask about an open-jaw ticket, or check about the change fee. The more flexible tickets can often be a lot more expensive than one with fixed dates. You can buy one way tickets, of course, and sometimes can get fairly cheap ones through discount airlines, but there's no guarantee that you'll be able to get a cheap one exactly when you're ready to go, so you have to be pretty flexible in that case.
I believe you can buy tickets that would cover you flying into one airport and leaving from another, but check with someone like STA travel to find out the best option for you.