I agree! It's frustrating. We usually go to Dick's for gear, but for clothes the options are limited until kids get a bit older. Nordstrom Rack. For our youngest we go to Old Navy. Inexpensive tees they out grow quickly.

Our daughter plays tennis and softball and we shop at Dick's for generic styles by good brands. For tennis specific we use online stores tennisexpress, tennis warehouse and tennis point. Though the selection is still pretty slim for kids. Amazon has decent selection but it takes forever to browse for the right stuff.

Online stores are the worst to buy

Avoid online stores at all cost