Based on our record, Keepa seems to be a lot more popular than Rainforest API. While we know about 80 links to Keepa, we've tracked only 1 mention of Rainforest API. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
You idea is known as a product comparison engine. When you sign up for an Amazon referral account it's one of the options. It's also similar to the CamelCamelCamel website. You might want to start with https://rainforestapi.com/ they have a hobbyist price tier. Getting access to all the data will be a big challenge, look at the stores and see if they have a product API. Source: over 1 year ago
I also recommend checking amazon.co.jp out as you'll have the option for certain products to ship to a konbini closest to your lodgings for pick up (they e-mail you a QR/barcode and you show it to the attendant; if you miss the pick up, they automatically return and refund you). This is especially useful if you're short on time and will help you streamline your itinerary so you're not going super far out of your... Source: 5 months ago
When buying off Amazon, always use https://keepa.com/ to track the price and get the best deal. Always read the seller reviews (product reviews are usually fake and useless). Source: 5 months ago
PSA: You can use a tool like Keepa to view historic prices of items on Amazon. It's a browser extension that injects into Amazon's website underneath the initial product listing. Will show you normal prices, the used prices, if the price was a lightning deal (a la Prime Day etc). Source: 10 months ago
Keepa.com is actually better. I have been using camelcamelcamel for years, but it started to NOT show the correct historic for a few items. But the keepa extension solved it. Source: 10 months ago
Keepa.com is my go to site for price history. Source: 10 months ago
cloudlayer.io - Automate your content generation
Camelcamelcamel - Easily monitor Amazon product prices and get alerts when they drop.
Canopy API - The modern API for Amazon data.
Helium 10 - Our software contains multiple Amazon seller tools to help you find high ranking keywords, identify trends, spy on competitors, & optimize product listings.
Amzapi - Our amazon product API enables you to scrape product related data.
Savelist - Found products you want but not ready to buy?