essential oils for fly repellant

["Glenda R. Snodgrass" <grs@theneteffect.com>]

As fly season fast approaches (actually, they don't ever leave us down
here -- just saw some today :) I'm starting to think about fly spray. 
Does anyone know of a good source (mailorder I guess) for the essential
oils used in the all-natural fly spray recipe?  I can buy them locally at
outrageous prices ($9 for 1/3 ounce) from a local vendor, but would much
prefer buying a whole summer's supply at reduced prices, if at all
possible.  

Surely some of you California people know a good supplier! <bg>

Glenda & Lakota (I smell sooooo good in summertime!)