Generally speaking it is based on the Clubs market. Whether it is a Big market team, such as the Chicago White Sox or the New York Yankees or a small market team such as the Tampa Bay Rays or the Kansas City Royals or something in between. The market is based on the size of the city's population and the teams subsequent fan base.
Big Market cities like Chicago and New York draw lots of fans thus drawing lots of revenue for the team to spend. Whereas, Smaller market clubs draw less and therefore make less money.
A teams relative success of course has something to do with the size of the fan base as well. Therefore a team like the Yankees who have won as many championships as they have also will draw bigger because of it.
Higher salaries make players work harder to get even higher salaries.
All teams that are soccer or football franchises have 11 players.
California, Giants, A's, Angels and Dodgers. Wait, what about the Padres? Question Fail.
The American Association of Independent Professional Baseball has fifty-four teams/franchises. For example this includes teams from Cleveland and Philadelphia.
Mike Morgan played for 12 franchises from 1978-2002, more than any other player.
Players negotiate and sign contracts with teams to determine a certain amount of money over a certain period of time. Teams can trade players (and their contracts) with other teams if they feel the need to. The better the player, the more money he will negotiate for.
You can find a list of the current player salaries at http://sports.espn.go.com/mlb/teams/salaries?team=stl
Value of franchises (per Forbes) is Cowboys, Redskins, Patriots, Giants, Jets.
For the 2006 season, the total for the 30 teams was well over $2 billion. Check out the '2006 Team Salaries' link on this page to see the salaries broken down by team.
Celtics have won 17 championships, and Lakers 16 - the two teams with the most championships. So yes, in many ways they are the most successful franchises in the NBA.
Bert Bell was the co-owner of two NFL franchises. The Phildelphia Eagles and the Pittsburgh Steelers.
I count 11 franchises with non-animal names which have won the Super Bowl.