Don't try to chip from the rough, even though that's what it defaults to. Pitch.
Wedges are cheap and worth their weight in gold. First purchase.
Don't get addicted to paying by the stroke. (Buying balls.) It's about being able to predict and reproduce behavior. When you get to the point you really believe you didn't finish top ten because you couldn't stop one approach shot on a dime or if you had only had an extra five yds on the par five, then you can think about buying balls. Clubs, on the other hand...
Play the default equip until you just can not improve your game any further with them. The low level equip just isn't that much better. Unless you can afford a new set every month for the first four or five months, just stick it out until you can buy good stuff. That being said, you buy game in the pro shop. The good stuff is good stuff. If you still love playing after three months of hacking with junk iron, it's worth every penny.