If the primary goal is saving money, and you want a new Prius, get a base "Two" model. The doo-dads don't help fuel economy or reliability, but sure cost a bunch! The doo-dads can, however, make for a more pleasant driving experience. To figure gas cost savings, you need to compare it to the other cars you're considering. You won't save anything in the long run over something like a Yaris, but you'll save a bunch over other new cars with equivalent cargo capacity.