Straw Hats
Straw is the plant material you have left after threasing oats or wheat. Threasing removes the grain itself and straw is the stalks that are left behind. Straw has almost no nutritional value so it was traditionally used as bedding in the stables.
However, if you take the straw and turn it into a hat it becomes quite valuable. Like many folk art activities what was once done out of poverty and necessity is now done as a fashon statement. For this reason the straw hat is also a popular motif in decorative ceramics and items depicting kids on the farm and other timeless metaphors.
I think "straw" is a very loosely interpreted word and most "straw hats" are not actually made of straw. There are many other materials; raffia, cane straw, Ecudorian straw, all being mentioned.
The problem I see with buying or selling straw hats on Ebay is the shipping cost. You probably don't want your new hat smushed into a box so I see shippping quoutes of $8.95 and up being quoted by sellers. My thought would be to look through the Ebay straw hat listings to explore the styles, fabrics and materials available and get an idea of cost and what you like. THen when you go shopping locally you will have a better ifea of what you are looking for.