Ask HN: Interfacing with Big Business

I'm pursuing an idea I had the other day, and in order for the product to function, it would need to get data from large retailers. However, these retailers, upon inspection, have very non-programmer-friendly sites (IFrames and embedded Flash), and no APIs to speak of.

Without this convenience, the product would need a LOT of (my) manual labor, something I don't have the time for at this juncture in my life.

So, I was thinking about sending emails to these businesses, asking if they had more programmer-friendly versions of their data, or something along those lines.

Is this a good idea? What would you suggest?

tl;dr Should a nobody like me ask (multiple) large retailers for access to their data? How?