You can't get the NAV system in the lower priced option packages in the Prius. I still bought the Prius without the NAV, but was tempted by the HCH because I could get the NAV for an extra $1k. In the Prius it was going to cost me about $4k in upgrades that I did not really want. So I just use my handheld GPS when I really need it, which isn't really that much.

Prius 06 Black Pack#2