Return or onward bound ticket requirement, how do you get around this?

I've been living here for a year extending my tourist visa. I want to go back to the US for a vist, so my round trip ticket will start and end here in the Philippines. I know it is required to have an onward bound ticket, but is there a way around this. Do you buy a cheap one way flight to some place close and then just throw the ticket away, or can a travel agent get you a ticket that you can get a refund on. HOW DO OTHERS IN THIS SITUATION GET AROUND THIS?