There's some peculiar names for it circulating around... Garnish is one name. Here's best price but only primed, not painted: Primed Rear Tailgate Liftgate Garnish Handle Trim Fit For Toyota Prius 2004-2009 | eBay
Thank you. I hope more names are dropped here to open up an expanded search, since that particular piece won't work. Edit: trim. Between those I found quite a few options, even on Walmart of all places.
Walmart robots are trying to compete w/Amazon even if they don't stock what they sell... I've been tempted by them for past few years many times, but never gave them my money. Can you please post the best options/prices after your purchase? I got more than one person looking for a good price on one of these.
A few weeks ago there was a thread on this due to accident damage with places to buy new one. Do a PC search and see if it answers your questions