There is a stand called "Main Street News" in the city on your way to the park, go straight, then right and its a little booth right in front of the PRO-AM arena. Just visit him every time he's open and eventually a Main Street News t-shirt will show up in your closet in your MyCourt. You need to wear this shirt and visit the Newsstand when its open, if you don't have the shirt on you can't buy from the stand. The guy in the stand will talk to you and you'll have the option to press
which lets you in the shop. The cheapest skill boost in there is 200VC.