All essential gameplay content is free for all players and the only thing that costs money are non-essential skins that don’t affect gameplay. There are no stat boosters or anything like that. Every player is on a level playing field and gets to enjoy all gameplay content.
The people whining over paid skins need to get a grip. If the only reason you play Overwatch is to collect skins then it’s time for you to move on because this game is not for you. There are games such as The Sims and Animal Crossing for skin collectors.
Overwatch is a competitive shooter first and foremost. Skins are simply there as a bonus for players who like the game enough to support it with money. Think of them as a thank you from the developers for leaving a tip.