The biggest way to make money to pay for the sub that I haven't really heard yet is actually playing the game. I know I'm not the only one that refrains from playing much else when I have an MMO to be addicted to. I believe that playing an MMO prevents a lot of people from buying other games that come out. Even if you want to play the title you can wait for it to go on sale or buy it a month or two later used. Oh how I love Steam.
Trying to reintroduce some sanity back into proceedings (yes, I'm saying there was
sanity ... at some point) - this is qft. When I'm neck-deep in an MMO, a fortnightly movie will be maybe a twice-monthly movie Not going out on a Friday is no longer a problem - just jump into a raid! A new game every month becomes "oh, Steam has a massive sale on, might check it out." You tend to be much more efficient with your "real-life" time, as there's always one more level/quest/drop to get. BOTH aunts & grandparents are in town? Sweet, months of family time crammed into 1 afternoon!
When I was working shi**y casual jobs & barely keeping my head above water financially, FFXI was a lifeline, giving hundreds of hours of entertainment each month for the princely sum of $14.99 (AUD here). Great value!