I bought my 2010 prius in June 2009. 31000 mile later my passenger side low beam head light bulb goes out. First I dint think that the bulb would be covered under the 3y/36000 warranty. I called the dealers part department to find out to my shock the the tiny bulb would cost $ 156.00 (part only) .looks like a simple DIY install according to the OM. The parts guy was nice enough to let me know that it would be covered under the warranty . So i dint have to pay anything this time. However $ 156 for a small bulb sounds ridicules to me. My prius will be out of warranty in just another 5ooo miles. i love my prius.
Well, you could have converted both low beam bulbs to HIDs for less than half that! You sure they weren't quoting the price of the entire headlight assembly?
Unless you had the model with the LED headlights (which you don't by your profile info), the healights can be had for about $20 for a pair at Pepboys. It's simple as pie to remove & install the new one. The passenger side is a little more involved, as you have to remove a bolt and lift the intake hose out of the way. I recommend going the HID route, but that's my personal preference.