I need a Python-based tool that takes a list of recent textbook ISBNs (last 3 years), pulls real sold prices from eBay, and compares them to current buy prices on AddALL, BookFinder, and Amazon (optionally AbeBooks/ThriftBooks). The tool should calculate fees, estimated shipping, net profit, and ROI, then export everything to CSV/Excel with a clear BUY/SKIP recommendation for each ISBN. Please quote for a stable Version 1 that I can run regularly, plus what you’d charge for future small improvements.