Wow, this site searches many of the airlines for the best flight to and from Roatan. Also combines airline itineraries for the cheapest fairs. A great feature is graphs showing the best days to travel, what the rise and fall of costs have been over the past 90 days. Kayak.com features pricing on hotels, cruses, car rentals, travel agency deals and more. Sure there is priceline.com, expedia.com and travelocity.com (to name a few) and this site actually searches those too for you. Play around with kayak.com from your city and get a great persepective of the best flights/costs for you.
It should be noted too that cheapflights.com allows you to put in flight parameters and than as a second step select one of the MANY online ticket websites mentioned above and search those real time all from one website. Pretty cool!!!