This report from The Insider online says each DWTS star gets $200,000 for being on the show no matter how soon they're voted off, with bonuses if they stay in the show to the end, with the longest stayer getting the highest bonus.
WikiAnswers says all the professional dancers get paid $5,200 a week. The celebrities get paid about $250,000 if they stay all nine weeks.
Here's WikiAnswers statement on what Jon and Kate made per episode of J&K+8. If it's true (and I'm sure it's not) that they as a family made $22,500 per episdoe, TLC got one hell of a deal. J&K+8 was TLC's highest rated show ever, which means they made more commercial revenue during that show than any other. Considering the high commercial revenue and Kate's financial savvy and insistence on only the best, $50,000 - $75,000 per episide is a much more realistic figure. Hopefully the kids had their own salaries and that money has been put into trust for their futures. After all, without them there would have been no show.
This link to Extra Online tells the salaries of several reality TV show stars. They report Jon and Kate made $75,000 per episode, which I believe to be accurate. J&K+8 became so popular that season three had 31 and season four had 41 episodes. When you compare the J&K+8 salaries of a half hour show taped in and around the convenience of your home (generating a total of anywhere from $400,000* to $3,075,000** per season) to an entire DWTS season of having to practice dancing for hours a day and the hassle and exhaustion of traveling 3,000 miles for weekly tapings for a grand total of $200,000 and maybe if you're lucky $250,000, which is really the better pay?
*based on minimum salary of 8 episodes at $50,000 per episode for season one
**based on maximum salary of 41 episodes at $75,000 episode in season four