If you have a groupon in the area, that's the way to go. The payout with those are great. I've bought stuff that I would have bought anyway and not only saved money from the groupon but got something like 850 credits for it.
On the RG's, having the Tour Pro tier has made all the difference for me. I average a 69+ and make about a 50% return (100 credits = 150 credit payout on average). Basically, if you can shoot -1 to -2 on Beth Page and Par to +1 on Oakmont, you make more money than you spend.
Ill admit I had to buy the Ping putter that makes the bar move slowly and a nice set of Ping irons for the same reason. Otherwise, I would just find 1 or 2 courses that you think are really hard and just play the heck out of them. For example, I have played Bethpage so much now that I know on each green that even though the distance says 155, for example, that I have to hit it 174 to get it to the stick. Once you get to that point, you can make money (err...credits).