If you need a DNA test it, I encourage you to look at this Family Tree sale. Their Family Finder test (autosomal test) is on sale for $79 - same price as the Ancestry sale. The major advantage I have found is in testing elderly relatives, who sometimes have difficulty producing enough saliva for the Ancestry DNA test. The Family Finder test uses cheek swabs instead.
Also, Ancestry offers only the autosomal test, while Family Tree offers the Y DNA test kits (for your father's line) and the mtDNA kits (for your mother's line) - also on sale.