Neal & Trish, I always find Ebay to be a great source for large quantities of Daffodils.
There are 2 typical sources on there. One are home gardeners that have tons of bulbs that are overcrowded. These folks often sell them in 100's or box lots. A lot of times these are from much older plantings, even before the home's current owner. I've gotten some nice pricey, hard to find Heirlooms very cheaply this way. Many are fragrant.
Another is that Landscapers often buy their bulbs by the multiple thousands to get them as cheaply as possible. They will often order many more than they need and will move the rest out on Ebay. These folks usually sell in quantities of 250+.
If you peruse B & B's catalogue for which varieties will thrive in your area, then you can do an Ebay search for those varieties.