Part of their approach is to avoid direct competition with big names, why not find out their proposals on sites like Expedia and Travelocity. This and the lack of advertising budget and use of relatively small airports, leading to drastically reduce their ticket prices.
These cheap airlines rely more on tactics "by word of mouth" - if someone is looking for cheap flights from local airport to the city, inevitably sooner or later will fall on them, especially if you travel frequently.  This offers unique opportunities for cheaper travel across the U.S., whether vacation or business.