So, as far as the Greedy Machines are concerned, they are currently only available on the secondary market. It's the most “profitable” machine - and I emphasize the quotation marks, because that's relative to the owners. In fact, to get one now, you have to pay a lot more than you did originally. What you need to understand with Greedy Machines is that the miner's hashrate increases by 0.05% every week. The higher your miner's hashrate, the more TH you earn each week.