Answer
I just researched this for anybody else here last week. the cheapest option for one way is, by far, aer lingus via dublin ($346 usd one-way, all in if i recall). you can pay at the aer lingus ticket desk at mco, or at their city ticket office if they have one, or from a travel agency which will likely charge an extra $25 to $50 (and will most likely try to sell you a more expensive ticket).
