I am traveling to the Philippines from the US to see friends and travel for an unknown amount of time (between 3 months and 2 years). Everything I read says I need a roundtrip ticket. How do I get around that?
Without knowing where you are flying from originally and what time of year, you may find that a discounted round trip ticket is just as cheap as a one way. Which would cover your visa and entry needs. And depending on the fare class, you maybe able to change the return date, once you figure out how long you are staying (in worse case you throw away the return portion's value but do cancel the return booking).
You could also look at more expensive round trip airfares that allow date changes. Though if you stay a long time you could find the original fare no longer applicable and you would have to pay the fare difference when you changed dates.
Another option is the proverbial throw away ticket, find some really dirt cheap flight to any country outside the Philippines and buy a ticket.
Or the other extreme, buying a fully refundable airfare, then cancelling it and getting your money back.