If your DD is already FF'ing...the Britax Frontier 85 will keep her harnessed longer than any other seat. It's also the tallest High Back Booster on the Market. You can find them all over the web for $209...so barely over your budget, but worth EVERY penny. Our daughter is 5.5yo, 44lbs and 47" she loves her Frontier. It's easy to install [even in the 3rd row of our SUV], 2 cupholders, SIP and a non-rethreading harness...etc.