Your lead time may be too short. Generally, I can find affordable flights when I book at least 3 weeks in advance.

My tricks:

*I book ultra early. If I haven't booked Christmas by Halloween, I feel like a failure.
*I fly ultra early- the 6 am flight always seems to be the cheapest. Nothing like getting to the airport at 4 am. This year I did it pregnant and was throwing up in the airport bathroom from too little sleep and breakfast. Ahh, memories.

Thankfully, I'm generally flying NYC-Tampa, which seems to have a good number of flights.

The day of the week makes a difference, as well as length of stay. I just found seats on Frontier at $385 each, roundtrip with 1 stop, on Orbitz, leaving March 5, 6 or 7 and returning a week later. American Airlines is about $25 more. If you try booking tickets directly through their respective websites, you may find something cheaper. Also, if you call to speak to a human, you could pay $20 for the privilege.

Unfortunately, she's limited to a strict timeframe on this, due to her class/work/spring break scheduling. The earliest they can fly out is March 11. Coming back could be any time that week. If they fly out the 11th, they could fly back on the 13th, provided they can see and secure a place on the 12th.

Kayak lists flights in the mid-400s. Southwest's website has flights as cheap as $227. I'm using March 11 - 13.

I use Kayak.com, and others like Skyscanner.com -- both sites search multiple carriers and sites, and allow you to look at flights throughout the day. It's even better if you're flexible by a few days, you might be able to save a couple hundred dollars (especially off of a potential $1,400-1,500 trip).

Kayak lists flights in the mid-400s. Southwest's website has flights as cheap as $227. I'm using March 11 - 13.

Does Southwest include all the taxes and fees upfront? I think Kayak does, which might count for some of the price difference.

Southwest's website has flights as cheap as $227.

That's almost certainly for just the outbound leg. Southwest is annoying that way.

No kidding!! A main reason why I prefer to remain in the city of my birth, where all my relatives are, is that if I moved anywhere else, I'd have to spend tons of money visiting them. And waste our natural resources in the jet fuel...

Whoops. Yeah, Southwest also ends up mid-400s when you add both legs together. Sorry!

Right now my favorite site for finding decent prices for airfares is airfarewatchdog.com. One of its best features is the email alerts when fares prices fall.

My tip (totally useless in this case) is to buy tickets very early - at least a month in advance if you can and to be flexible about travel times. You can save huge amounts of money this way, as the airlines are well aware that people's choices get narrower and they are prepared to spend more money as the travel date gets closer. As TPS says, very early and very late flights usually sell much more slowly so you are more likely to have choice. Friday night, Sunday night and Monday morning are probably the worst times to try and get a cheap flight, so maybe they are better to travel a couple of days later than the 11th, if the departure date is flexible?.

Is it possible to drive to a different city and fly from there, or fly to a different city, then drive from there (would need to factor cost of a hire car)? Different routes, even over the same distances, vary dramatically in price.

I have no useful tips, just commiseration: How does a regular person afford to fly anywhere? ARGH.