Well, that's certainly efficiency lol
I like being a good boy, so since keepa offers a good amount of information for free, I went ahead and asked directly in their forums. I put it as a request for implementing it for Rainmeter use.
Maybe they don't know Rainmeter and once they meet it they like the idea and let us parse at least product title, image, lowest, highest and current prices.
They offer a user based RSS notification system. I'm not familiar with RSS, so I was wondering if theoretically they could report that info to an RSS and we could parse that to retrieve the data?
I haven't given up. (yet)