Can using GPS save greens on gas?

Yesterday i bought a Magellan 4250 GPS from Circuit City. I had been avoiding incurring this expense thinking i will use Google maps or MapQuest to reach the destination, but in spite of this paper copies i have gone in circles and missed the destination on number of occasion. Okay, I'm not directionally challenged, but due to detours as summer is the favorite time to repair the roads, i have wasted gas and time.
I plan to recover the cost of the unit ( i bought a open box item so it was cheap far less then $300.00) within 2 yrs time by avoiding getting lost and saving gas.

What do you guys think has the time come to categorize a GPS as a "Need" and not a "Want" and can it save some money?