What are your dates? If it's in the next few months, try your dates on farecast.com, and they'll indicate if they think the cheapest fares will be going up, down, or staying the same.
We're flying PDX to MCO later this month. We had a lot of changes to our group, so ended up buying tickets in June, August, and then again just last week, all at different prices. I watched for a few weeks before I purchased the first set of tickets, and the rates moved around up to $80 higher each way, with no particular date pattern I could determine. And PDX doesn't seem to get a lot of the "last minute" kind of cut rates to MCO that other folks report from other cities. All that said, it was cheaper in June than it is now for almost all the choices I looked at, although Alaska Air had a RT direct flight for $218.80 (incl. taxes) for our dates as late as this past week. That's just $20 higher than the lowest price I saw in June for that set of flights.
One thing I've noticed from PDX is that American Airlines often "code shares" with Alaska Air, and lists the same flights operated by Alaska Air but at different prices. In one case, the same 1-way flight booked through American was about $100 higher than what we booked through Alaska Air.
And one last consideration: if you want to buy now to "lock in" your schedules, I think both Alaska Air and Southwest will give you a credit towards future travel if the price goes down after you buy and you ask for the credit. On most other airlines, they charge a change fee (up to $100) even if the only change is a lower fare. So the price would really have to drop before you'd see any savings.
Good luck!
