It is very rare to see a publicly-available breakdown of the operations expenses for any pro baseball team. The JournalStar.com website in Lincoln, Nebraska published something of interest to anyone who has ever thought about the business of pro sports as it broke down the line items of expenses for the Lincoln Saltdogs (American Association).
While this is not the budget of all teams, it gives a good idea of what it takes to operate a legitimate independent professional baseball team which is worthy of having a long tenure. Kudos to the Saltdogs for being willing to show just how much is involved to break even on a particular year.
There are several good books about the independent professional baseball leagues. You are welcome to see a list of suggestions through this link: Books Get notified of upcoming independent baseball tryouts from either of these services: first service or the second service. Prospective players can find some helpful resources here We will be providing a growing list of possibly helpful tips and suggestions on various baseball information. This will range from "how to" information about baseball skills all the way to helpful information for casual baseball fans. Please click the link for more information: Tips And How To Information