Fortunate enough to get it all ( red and white oak, hickory, maple, pecan, apple, cherry) myself. Allen, contact some local tree (cutting) companies. They're always looking for ways to get rid of wood, and the small amounts we bbq-ers are after, you should be able to get it for a fraction of the cost compared to buying from a store. Also, become familiar with how the wood you desire looks like. If you drive by a house and see some wood on the ground, or see a person trimming trees in a yard, don't hesitate to stop by and ask for some branches. Again, free is for me, and a new friend might be made. Free wood is out there to be had, I just had to realize where to ask and look.
Good luck,
Tim