Alternatives to Business School

Hi all,

I am involved in non profit via the arts. I'm in my early 20's and looking ahead to a long career in upper management and directing organizations. I just graduated undergrad a year ago and began working, but am now questioning whether to go back to school for a MBA. Unfortunately, I don't have the funds or can take out large loans, unless absolutely necessary. Are there alternatives to Business school that are taken seriously from a hiring perspective? Certification programs or online programs? There seem to be a multitude and it is difficult determining which are of actual value.... Or is a MBA the only option? Thank you!