Used to get credits by becoming friends with somebody else, I think it was 50 credits for each new friend...not sure if this option is still there...
The old catch22 you need to have credits to win credits in the Tournys.. Eg; the Ready-Go's are 100 credits each and how well you do in them you can win credits
Join a Social Club... if they run Tournys for credits and if you shoot good scores, sometimes it could be cheaper.
-and of course you can use your credit card to get credits
Most of the time you need to be in the low 30's to get good credits back...33 being a Ave score to get some credits back....
I shot a 42 on Kiawah Front 9 last week (I think the hardest) and got back 50 credits., I have also shot a 33 on the same Ready-Go and got back 200 credits... all depends what the others shoot and how well you do...
Good Luck