My view is this game is free, you don't have to buy anything. You play and get better and you can choose to stay at that level or buy some clubs to get better. I have spent about $30 in this game of my own money. I have won about $90 in credits, I can't play the match play challenges.
I did the same as the above poster. I played the Oakmont qualifier after shooting a good score 62 to qualify, I thought I would give it a go with starter clubs and balls. I was able to shoot about 82 with starter clubs, I think if I had played a dozen times with starters I could get down to 72.
Before making the old master level, I was able to shoot about 66 with starters, bought a Rapture dirver and got down to about 63. Made master and got my average down to under 60. After the green speed and tee change, I struggle to shoot under 65.
I like it tough, it was too easy before, if you want to shoot 50 just go over to TWO and you can break 50 in a week.