CCP has implemented a form of controlled real money trading (rmt) using play timecodes. It is a neat system in which the only party that receives real money is CCP while players trade play time for in game currency (ISK). A consequence of this system is that players who amass a considerable amount of in game wealth can pay their monthly subscription using in game currency and thus play the game for free.
A quick look at Timecode Bazaar, the official forum for buying and selling time codes shows that there were over 450 separate posts on the 17th July. Not every post resulted in a sale while some posts resulted in multiple sales. If I somewhat unscientifically assume that this amount of posts equates to 450 sixty day time cards being sold on an average day that suggests that 60x450 = 28,740 EVE accounts are being paid for using in game currency. If this is true then about 11% of EVE's quarter of a million active subscriptions are being paid for with in game currency. It should be remembered that CCP lose nothing from this - they still get the money from those who purchase timecodes to sell for ISK.
That 11% figure is a crude guess but it tallies with my own experience of talking to more experienced players in game. Many of them, in particular established PVE players seem to pay for their game time with ISK and effectively play the game for free.
At one stage I even considered this as a potential in game objective for myself. From various sources I have read that an established player can earn around to 30 million ISK per hour of playing. Sixty day time codes are currently selling for 400 million ISK. So 13 hours of money grinding would pay for two whole months subscription.
Good value? Errrr ....No. I can buy the same timecode for around €22. Thirteen hours of grinding to save €22 works out at €1.70 an hour which qualifies as slave wages in any developed nation. For the moment I think I will hold on to my ISK to spend on fancier internet spaceships.
It would be different for a gamer who's preferred in game activities naturally generate a large surplus of ISK over and above their in game requirements. Hard core miners, mission farmers and in particular traders may well generate the funds required to pay for their gaming time merely by doing the things they would be doing anyway. This probably explains why the folks I see in game who play for free tend to be PVE players. PVE play generates wealth, PVP play destroys it.
In a previous post I commented on the abundance of multiple account players in EVE. The ability to pay for accounts using in game currency adds a new perspective to this. If a player sets up their alts as ISK earners they can run multiple accounts with little or no cash cost to themselves. Some activities like mining, hauling or trading can be undertaken with relatively little human interaction allowing a player to build up a self sustaining cohort of 2, 3 or even more characters all paid for by their in game earnings.