I think I know what the OP is referring to, especially when it comes to apparel. Both my boys play club soccer and fortunately, their two clubs are relatively basic when it comes to uniform requirements - jersey, alternate jersey, shorts and socks, plus a practice shirt. Everything else is optional.
Other clubs, however, require hundreds of dollars of gear - one, in particular, requires all their players to buy two uniforms, plus a full warmup outfit, personalized bag and a couple other things. It can get crazy.
While my kids don't play baseball, a lot of their friends do and that sport seems to go over the top when it comes to apparel - multiple uniforms that look like they're right out of the major leagues, plus equipment bags, etc. Plus, when you figure that kids grow out of the stuff each year (and it's all personalized, so you can't hand it down to anyone), it has to get crazy expensive.