If it's legit, it will be within a certain price range.
I sell parts online for a dealership. There are only a few ways you can adjust prices around and be competitive. Here are a few of the ways you're gonna be charged. Keep in mind most online stores are selling at ~C+20%
1. Pay more for the part, free shipping.
2. Pay more for shipping, cheaper part.
3. Promo Codes.
No matter what way you slice it, the prices will be roughly the same because there is a rock bottom price and online stores have hit it. If you see a part on Camelback Toyota for $100, for example, and another site has it for $50, I would be very suspicious of the cheaper price. I have seen Grey Market parts being sold as Genuine on some corners of the internet. Ebay is notorious for fraudulent Chinese parts being sold as OEM. I know this because they are selling "Genuine" Parts for cheaper than I can get them directly from the manufacturer as a Dealer.
I am not affiliated with Toyota online stores. Different manufacturer.