Okay, this may be a stupid question but here goes...

I'm headed to the Philippines on July 23rd on a one-way ticket. I've found out that I'll likely need to show proof of an onward ticket to board the plane. My thought was to buy a refundable ticket and then cancel it later. But having never bought a refundable ticket before, I'm a bit nervous about this. Will I really get a full refund of my ticket or are there hidden fees that I should be aware of? And how can I be certain that the fare is refundable? I was looking at Northwest Airlines, fare code Y2SOTO if that means anything.

Thanks!