I just started this past December so I will give the path that worked very well for me. These are just suggestions and by no means guidelines to follow.
I started out with using full starter equipment till about level 20. Since I was playing on an android device I found out about coin rental sets. They cost about 10k silver coins which are won with a level up or by playing a coin match to wager your coins against someone else. I started to rent the MK2 coin 7 day full set rental and used those clubs until you see where I upgraded in my chart below (they are just a touch better then the starter clubs) If you don't play on an Android device ignore the MK2 items.
Ball: Starter ball -> WGT Tour-SD Balls (65cr) -> Srixon Z-STAR Balls (180cr)
Driver: TaylorMade R1(L11+) -> TaylorMade R1(L48+)
3WD: TaylorMade R11 3 Wood (L30+)
Hybrid: MK2 coin 7 day rental -> removed from bag for 3rd wedge
Irons: PING i25 Iron Set(L36+) -> PING G25 Iron Set(L59+)
1st Wedge: starter wedges -> MK2 coin 7 day rental -> PING Gorge 60° (L41+)
2nd Wedge: starter wedges -> MK2 coin 7 day rental -> TM ATV 64° (L39+)
Putter: TaylorMade Ghost Spider Putter (L35+)
3rd Wedge: PING Gorge 56° Wedge (L41+)
Analysis:
Balls- There is absolutely no need to purchase balls until you upgrade your irons. I personally used WGT balls up until about lvl 40 and did fine. From that point on it is what you can afford but the two balls I listed are the best bang for your buck and work excellent for me all the way through Master. I currently use the Volvik Crystal ball (L51), but that is not necessary to spend 400 credits on a sleeve of 3 balls.
Driver- This was the first piece of equipment I purchased. Whenever you can afford either of the R1 drivers I mentioned you should buy them (specially at level 48 right after you rent it to get the 10% discount)
3WD- I did not upgrade my 3WD until lvl 55 or so since distance was not an issue with the r1 drivers. Once you get to the Master tier you will notice the missing hole between driver and 3wd and I would recommend to upgrade then. (Driver and irons are much more important)
Hybrid: The 190yd starter is pointless once you upgrade your irons. As soon as I upgraded my irons and could afford a new wedge I replaced my hybrid for a 3rd wedge and never thought about another hybrid again.
Irons- I went with the i25 irons as a first upgrade because of the little bit slower meter speed and cheaper then the r11's (L32) but the r11s are the better club so that choice is up to you. Saving credits and slower meter were more valuable to me at the time. As soon as you get L59 rent and then purchase the G25's. You will love yourself and your game will see a massive improvement (mine was huge).
Wedges- I personally stuck with the starter wedges and then upgraded to the MK2/MK3 wedges using the silver coins earned easily on android devices. As for the 3rd wedge I got this later then I should have and regret it. I waited till about lvl 45 to get the Gorge L41 56 degree. I would suggest purchasing any wedge that has a distance of about 90 yards after you upgrade your first set of irons. This will space you out well with roughly 50-70-90 for distances. Once you get to Tour Master (or have extra credits) look to purchase the ING Gorge 60° (L41+) and the Taylormade ATV 64° (L39+). This will leave you with a perfect gap between each club.
Putter- The starter putter is awesome, the ghost L35 putter is awesome. Upgrade at your convenience, but that is not necessary. At least wait till L35 to get a new putter, but you could wait all the way till Legend if you really want to.
A Few Tips that helped me:
-if anyone figures out a way to transfer silver coins or coin rentals reach out to me and let me know. I will gladly send you the MK2 7 day rental over.
-Make use of the Punch shot! This gives every club in your bag two distances as well as a way to make the wind less a factor. Practice the punch and use it over a choked down shot. This only works well for the lower irons and wedges since you can still grab some spin and stop it within 5ft of landing, even with a cheaper ball.
-Do not quit rounds if you are doing bad. Your AVG may be affected but once you hit the thresh hold for the next tier the bad rounds are thrown away and your average will drop quick. You can also learn something from watching someone beat you.
-Play ready-go tournaments early and often. I started late with learning about them but they are a great way to fund your club purchases. I know for the master tier read-go's you only need to shoot 1 or 2 under par (for 9 holes) to make credits normally and 4 or 5 under will win the tournament.
-Have Fun and if you ever want to play me in a game send me a request and I will gladly play if I am not in the middle of a round.
-USE THE EARN FREE CREDIT OPTION:
I have only purchased 2,000 WGT credits with my own money (since they had a special to get 500 free credits on my first purchase and 3 free balls and removed ads which were annoying anyway). I have done a bunch of the Trialpay options to earn free coins. The redbox free rental was an easy one for 700(cost $1.99 and you ge ta free movie rental and some coffee), the stamps.com was free and I think 2000 credits. The Groupon one got me 600 for a Groupon I was already going to buy. The heartwood and oak wind club was $9.99 but I got two bottles of wine and 1200 credits. I downloaded the rhapsody app and signed up for a free trial then cancelled it for 1200 or so credits. There are tons of offers you can do specially the install and app and then delete it ones to earn a ton of credits.
MAKE SURE TO CANCEL THE SUBSCRIPTION RIGHT AFTER THE CREDITS ARE AWARDED OR THE FREE ITEM IS SHIPPED. If you do not they may send you a surprise second shipment and charge you $60.