I play in the NFBC, which is run by Krause publications. There is no trading, which I had to get used to, but have learned that no trading is really much more fun and much more challenging.....and much more fair.
http://www.fantasybaseballchampionship.com/
The regular league cost is $ 1,250, with a $ 5,000 payout if you win your division & $ 100,000 if you beat everybody ( about 300 people ).
The also offer an Ultimate League which is a self contained division. It cost $ 5,000 and if you win your 15 team division the prize is $ 40,000
There are also significant prize $ in both leagues for 2nd and 3rd place finished, division & overall.
They also offer satellite leagues which are self contained divisions.....$ 250 division pays $ 1,900 to the winner of the 15 team division....$ 500 pays out $ 4,000 and $ 1,000 pays out $ 8,000.
The satellite leagues draft over the internet, the others draft in Las Vegas, Chicago, New York and Tampa Bay
If you're looking for a safe 5 X 5 mixed non-keeper I'd highly recommend the NFBC ( National Fantasy Baseball Championship ).
If you play in the $ 1,250 league you'll be competing against Meatloaf & Chris Moneymaker ( poker guy ), among others.