Re: Upgrading apparel and equipment
If you want to upgrade club performance you need Specs, with all other things you can buy being cosmetic only. What you need to buy any of these things from the store are Reward Points (that kind of look like gold coins). The best place I think to earn these is the daily/weekly/seasonal tournaments. There's a free to enter 'daily' tournament every 12 hours that will allow you to earn up to 1500 reward points and it's only 4 holes so doesn't take long. Reward Points can also be earned through some Challenges and Quests.
Sponsor challenges can earn you cosmetic upgrades directly too.