GameStop just made an unsolicited proposal to acquire eBay in a deal worth roughly $56 billion.  GameStop CEO Ryan Cohen told The Wall Street Journal that together the two companies “ could be a legit competitor to Amazon .” He added, “EBay should be worth—and will be worth—a lot more money. I’m thinking about turning eBay into something worth hundreds of billions of dollars.” Cohen sent a letter to eBay Chairman Paul Pressler on Sunday offering to buy the company for $125 per share in a deal split between cash and GameStop stock. The proposal includes an ambitious cost-cutting plan for eBay. Cohen said the company could slash $2 billion in annualized costs within the first 12 months after the deal closes by reducing spending on marketing, product development, and corporate overhead. A major part of the pitch also focuses on the overlap between the two companies in categories like trading cards, retro video games, and collectibles.  Cohen proposed using GameStop’s roughly 1,600 U.S.…