Have you looked at the Allegiant Airlines route map lately? While other airlines are dropping routes, this scrappy low cost carrier is adding them. One of their latest cities is Grand Rapids, with nonstop service to Orlando/Sanford and St. Pete. With few exceptions, Allegiant connects smaller airports throughout the US to warm weather vacation and convention destinations, such as Las Vegas, Orlando, Mesa AZ (near Phoenix) and St. Petersburg.
Allegiant holds frequent "sneak" sales with fares as low as $15 each way, and constantly fiddles with its pricing, which certainly keeps us on our toes. Although they have many extra fees, most notably a $13.50 charge for booking online or $10 per segment by phone (no charge if you buy at the airport) their fares are consistently low, and the flights are almost all nonstops. Like Southwest, Airtran, and JetBlue, they also sell all their fares one way for half the round-trip price. And unusually, for $50 you can change the passenger name on a previously purchased ticket, so you can transfer the ticket if you can't use it.
Allegiant is also one of the few profitable airines in the US right now. They keep the bottom line healthy by selling vacation packages and ancillary services like shows (such as Blue Man Group), rental cars, and tours.

One thing to look out for when booking on their site: if you just want airfare and not a package, be sure to click the "Flight only" button on their booking engine. Enter your travel dates, and you'll automatically be shown a flexible date calendar showing which fares are available those months. Use the arrows to search subsequent months and you may find lower fares. We've found that they often launch their best sales on Saturdays.
Allegiant's fares do not appear on online travel agencies or fare aggregators, and are only sold on their own site or over their reservations line at 702-505-8888 (yep, it's not toll free). Airfarewatchdog researches and reports on their fares route by route seven days a week, 365 days a year.
Currently, Allegiant is accepting reservations through July 31, 2009. Sign up for their emails, since they sometimes send out promo codes that will clip a few dollars off of their regular fares.
And in case you were wondering, Airfarewatchdog has no monetary relationship with Allegiant. They don't advertise with us or pay us commissions. Heck, they probably don't even know we exist.
What do you mean by "kept locking me out"?
Spirit does have problems with their web site, they recently updated it to help prevent these problems from occurring by timing out a session. Also, inventory goes very fast, so as soon as you get an e-mail, get on their web site ASAP. In fact, I have Spirit's sale link as one of my home page tabs, just because sometimes the e-mail comes in slow. For example, check the time the e-mail came in vs. the time the sale started, if it's been hours since the sale started, then inventory may already be gone, especially for the prime dates like weekends.
@Matthew
I'm sorry to hear about the problems with people not reading, as it's quite a simple thing to do, it's not like your web site is a novel, lol. I have noticed a few times that you guys link the wrong URL for Spirit's sale, so that could cause confusion as well. Most non-member RT fares are $40 more, which is the cost of the membership. However, I've seen non-member fares as low as $18 more, it varies.
Now if this person you're referring to was seeing the non-member discounted fares for $20-9 more each-way, then she could have easily booked the slightly more expensive fare or purchased the membership since inventory was obviously available. That said, if the regular airfare was showing, then I believe the $9 fare club fare is also gone. Although I haven't checked many times, I have logged in, seen $9 fares, logged out, and then seen the same fares for $9-20 more. According to Spirit, $9 fare club members have a better chance of getting the cheap seats, but I just think that's just to lure people to sign up. I signed up because the non-member fares were $40 more and I was buying 4 RT tickets at the time [now a total of 15 RT tickets].
So regardless of the airline, inventory disappears all the time and if that woman can't find it, too bad, she was just too late, and it's a dog eat world out there in case she's new, lol.
Sorry to hear about your problems, in the future I would book your tickets online as soon as you see them go on sale, most airlines' web sites don't have a booking fee [except Allegiant] and if you want to go with a travel agent, Priceline doesn't have a booking fee.
Even though you would save almost $30, when you consider the time/gas/etc expenses you would incur going to the airport, it's probably worth it just to buy online, especially since then your ticket price would be locked in.
Good luck next time!
@Matthew
This web site isn't affiliated with Allegiant Airlines Corp, so they can't do anything to offer you a frequent flier program. Most airlines have a program like that, but not Allegiant. My advice to you is write to the company, as they probably take a look at the demand for that and may deploy such a program in the future if people like you ask for it.
Good luck!
@Matthew
@Matthew
I'm half thinking of not posting them anymore, because people just don't read. I got a call the other day from a woman who said we were "advertising" "fake" fares... she wasn't a member of the $9 Club but she was trying to book a $9 Club fare!! I said, "Madam... Madam... please... would you please listen... Madam... You HAVE to sign up for the $9 Club to get that fare...." "Where does it say that? It doesn't.... oh, must be a member of...." and her voice trails off. Anyway, I digress.
Another thing I like about Allegiant, however, is that I think they have a better chance of survival in a downturn than some other airlines. Not sure what their Q4 results were, but even Southwest lost money in the last quarter.
I agree with Klaka about Spirit as well, they are amazing, they actually fly to the big airports [ORD, DCA, BOS, LGA, DTW], and have great $9 fare sales. Plus they fly all new Airbus 391 or 321 aircraft, which doesn't have the dreaded engines mounted on the tail like the MD-80 series Allegiant flies. I love Spirit, I've flown more than 9,182 miles with them, but only paid $112 in airfare [excluding taxes]. Pus that doesn't include two more $9 trips I have booked in February to FLL and then to STT. I love when I'm able to book $9 tickets to FLL, and then onto one of their many other destinations. FLL is a nice layover/stopover airport!
@Matthew