The best $400 bow is a used $800-$900 bow.
I would go to a good bow shop and shoot some of the top brands (i.e. Mathews, Bowtech, PSE) and determine which brand appeals to you, in terms of 'feel.' While each model is unique, these brands each have their own characteristics. Once you find a brand (or two) that you favor, and maybe a few models) start researching the precursor models from previous years. The changes that exist in the newest models will be minor. Find a used model that's in your price range.
I'd rather have a high quality used bow than an inexpensive new bow.
I just found a 2 year old Mathews Z7 Extreme fully equipped with top of the line accessories and a case for $575 for a friend's kid.