I have a 2004 Prius with 166,000 miles that, till yesterday, ran just fine. Now, however, it has a bad inverter converter, and the Toyota dealership mechanic said it's going to cost $4,200 to replace. Can I safely buy a used inverter converter from eBay and insist that the dealer's service department use it? (Will a dealership's service department typically agree to using used parts provided by a customer?) I see used ones on eBay for a couple hundred dollars or less, which sounds a lot better than $4,200. Are there any considerations I need to keep in mind when selecting a specific used inverter converter? (I see about half a dozen on eBay that should work on a 2004 Prius.) If the used part is a bad idea, then is it crazy to spend $4,200 on an 8-year-old car? I don't want to find that I'm spending $2,000 next year, and so on, but neither can I afford a new car right now. Thanks for any and all insights.