Amazon and Half Product Info via API

We have a customized software for our textbook business. In addition to selling books in store and on our own website, we sell books on Amazon and Half.com. Currently, we manually enter the Amazon and [login to view URL] price of the textbooks that we have in stock. We have to manually update these prices a few times a week. We would like to see if there is a way that we can get all of the Amazon and [login to view URL] textbook information and pricing information uploaded into our software on a daily basis so that we constantly have the updated prices. We already have an algorithm built that will tell us where to list the book once the prices are in. We also would be interested in getting the Amazon trade in or buyback price for each textbook. Honestly, I don't know too much about development stuff. I am not overly satisfied with our developer and he doesn't seem to know much about Amazon and [login to view URL] API's. Looking for someone who has already done projects similar to this to save on time and money. If this can be done, I can get you more information about our software but you will have to let me know what questions you have specifically so I will know what to ask our developer about our software.