Like Bossbird says, it IS possible, it just takes time and practice. The way they (WGT) have set it up now you will advance through LEVELs fast enough to get upgraded gear, if you are patient. But if you don't practice and learn the different courses,
the fancy new clubs won't help all that much. And as you say, coins can be hard to come by, and they don't do Sh^+ to help with new clubs/balls.
As also said, coins won't do d!*k for you in this game unless all you want to do is play more coin games or update your appearance.
If you want to play seriously without outlaying some cash you need to put in some time, both in the game to learn the courses, and in the endless watching of videos for 2 credits, doing offers from Tapjoy/ReVue, etc...