How many place winners receive money in the Kentucky Derby?

Answer 1

For Derby #135 (May 2, 2009) the owner gets the money, but will be contractually to pay the trainer and jockey a certain fee (usually between 10% or 15% of the purse.) From the courier journal:

If all 20 horses start in Saturday's Kentucky Derby (Derby #135, May 2, 2009,) the total purse will be $2,210,000, with $1,450,000 to the winner. That ranks third all-time. The record purse came in 2005 - the first year Churchill guaranteed a purse at least $2 million. Giacomo netted $1,639,600 of the $2,399,600 purse that year, which included a $200,000 supplementary entry fee owner B. Wayne Hughes put up to make 11th-place Greeley's Galaxy eligible to run. Last year's purse was $2,213,200, with Barbaro earning $1,453,200. Of the Derbypurse, $1.11 million comes from fees paid by horse owners in early and late nominations to the Triple Crown, as well as the $25,000 entry fee and $25,000 starting paid for each horse who actually competes in the race.

Answer 2

In betting, only the first 3 finishers receive money in the Kentucky Derby (and all horse races). However, in terms of purse distribution, money is paid out to the top 5 finishers in the Derby. Prior to 2005, only the top 4 Derby finishers received any purse money.