Here's my take on headlight bulb replacement. I have the HID bulbs but I'll point out the halogen differences as the job is nearly the same. If your Prius is still in warranty or even slightly out of warranty check into the , you may be able to get the replacement covered. For those who are out of warranty like me or have halogen bulbs read on. This is really a simple job (actually the first job I did on my Prius), it doesn't take long and you'll save a ton of money doing this job yourself.
Replacing headlights is a common DIY repair procedure. You can refer to this headlight replacement guide to ensure that you have done your installation right.
Let's face it: you're busy, and a headlight assembly replacement shouldn't have to be a pain. You need something that fits, something that works, something that's reasonably priced, and you want that something as soon as possible. You don't want to get it wrong, but you don't want to spend too much time on it either.