20 teams, mixed AL/NL, eBay-style online auction, minor and major league rosters, weekly transactions. Each team's W-L record is based on the runs created by their lineup and runs allowed by their pitching staff. Teams earn revenue based on their record, and pay player salaries - so a team can still be profitable even if it does not win its division.
$14 admin fee to cover CBS Sports and web hosting for the auction site + $36 refundable deposit to cover potential losses.
This league has been running for over 12 years. The keeper format ensures that owners stay engaged throughout the season, whether they are rebuilding or going for the title. Limits on keepers ensure a big free agent pool and that every owner has a chance to win every year, while allowing shrewd owners to build powerhouses. There are 3 open spots - the new owner can take over an abandoned team (first come, first served) or start clean.
Email if interested and I'll send you the rules and an invite to the CBS Sports site so you can take a look at rosters and the free agent pool.