Infinite Minigolf

This is more quickly done by playing the Quick Play mode to run through some of the easier, user designed holes. Each has an objective... very often, easily obtained, that results in getting you playing cards whose values can be traded for avatar items (golf balls, clubs, eyeglasses, hair, shirts, pants, etc). Quick Play is quicker because the holes are easier to make the objectives, so you can build up a lot of cards quickly.

You don't need to get in too much a hurry for this because there are also other side goals along the way (get a hole in one, use a special type of power-up.... buy a special avatar item). I just waited for the "buy a special avatar item" goals to come around and then went to the avatar store (X from the main menu) to select an item of the type required.

The only trouble for me was that one of the first types of avatar items I needed was hairstyle and I was building up lots of cards for all other item types, but none for hair until after quite a while.