Just what gw lit said...generally get a couple a day...some days less and some days more. The Ding fares (from what I can tell) do tend to be better priced, but I think are kind of limited...so from what I've read here...if you get a great price...jump on it. Also, when I talked with a SW rep, she told me that IF I booked an internet fare, then got a better Ding, they would credit me the difference. Glitch is that the credit must be used within one year of the date it was purchased. I know that was confusing so here's an example...
I buy airfare on SW on June 1, 2005, STL to MCO, roundtrip, at $200 for travel dates of Nov. 10 and return on Nov. 20. On Sept. 5, I find a Ding fare for the same travel dates costing only $100. SW will credit me the difference of $100, BUT I have to use it for travel by June 1, 2006. Or at least that is how the SW rep explained it to me.
I'm willing to take a credit, because I'm looking at doing some travel for work within the year, so I could use the credit for that...or heck, just might have to make vacation plans again so I don't loose the credit...oh, darn...lol
Another suggestion is to sign up for the SW emails on their sales and such...they had a great sale price for July 4th...traveling only on that day, but if we hadn't already had plans we could have gone to WDW for the day for about $100 per person. Yeah, that is a bit eccentric, but if I had the extra cash hanging around and nothing better to do, what the heck. Right now there are some great deal for traveling late August.
Hope this helps some more...and don't ever worry about asking too many questions...that is what the boards are for...to share our love and knowledge about WDW and those things related.