I keep thinking that a virtual arcade model could work well... you get N plays per day for free, but if you want to buy more &quot;coins&quot; you pay like $5 and they carry over...<p>Each version improves existing games in the arcade and&#x2F;or adds new ones... you can play your 20 coins&#x2F;day first, then buy extra if you choose... there&#x27;s no reason that model couldn&#x27;t work quite well.