What brand of vodka is best for use in home made vanilla extract?  Please keep in mind that a $100 bottle is beyond my means.  I plan to make six cups of extract.

A $100 dollar bottle of vodka would be a complete waste of money, given that 1) vodka is essentially tasteless anyway, 2) a teaspoon or so is spread out over a large baked item, and 3) most of it boils away.  Buy an inexpensive bottle.