Yup Inter, Milan, Lazio and Roma sold players to each other for ridiculous sums in the last decade. They brought themselves on the verge of bankruptcy. I've read it years ago that Berlusconi came to this idea. The catch is when you buy players it's considered as an investment and thus it isn't part of an income statement meaning it won't influence net profit directly. But on the other hand selling players is a revenue and it increases net profit of the FY. Naturally after couple of years of these transactions their amortization costs were abnormal.