In recent years, there has been a huge surge in leagues forming which charge prospective players with a pay-to-play business model. Most say that they can get you signed to at least an independent professional league, but this is not always the case. It is an unfortunate situation, as many prospective players have had challenges in recent years attending these winter/spring developmental (instructional) leagues only to walk away with nothing of real value.
Here is a video clip from the Pecos Spring League which runs in March in South Houston. It is owned by the commissioner of the main Pecos League, so players do get exposure to Pecos League managers as well as instruction from them in hopes to get better and earn a spring training invitation.