The LE is the interesting row. It is the cheapest Prius and also the most efficient one by a clear margin, because it sits slightly lower than the trims above it and slips through the air a little better. Buying up the ladder costs you fuel economy on this car, which is not how most lineups work.
Deals move month to month, and the current new Toyota specials show what is running now. You can start a financing application or get a figure on your trade before you come in.