Go to the get free credits section. You can watch videos and take surveys to earn free credits. Beware of the other offers. You will be swamped with spam, and calls from telemarketers trying to sell you things.
Most offers like that have an option to opt out of contact. But it doesn't work. They will contact you anyway. I've been playing since October 2014, and have only made 2 deposits. $20 of which went to take advantage of a free ball offer. So it's possible, it just takes time.
If you're still using starter equipment, try getting better with that first. Especially the starter balls. You need much better equipment to take advantage of higher $ spin balls. It won't be available to you for a while. The biggest game changer is the lvl 59 Ping G25 set. Irons have high trajectory, making for softer landings and less roll out.
Good luck and enjoy
phred952