I checked the prices for Cirque du Soleil shows, and got shocked. The tickets range from $99 to $165. Any advice on where to buy them at a better price? Thank you

Typically, Cirque du Soleil shows have absolutely no problem selling out at the face value. Indeed, scalpers often get even higher prices.

So discount tickets tend to be hard to come by.

for what city and show?

Join the free Cirque club (on the Cirque du Soleil website) and there are occasionally discounts, especially for the traveling shows. I got the last NYC show at 30% off through the club

If you are looking at the Vegas shows, I know that when we were there in Feb you could get discount tickets to Mystere but no other Cirque shows.

Sorry! I forgot to specify that I was talking about Las Vegas Shows. The ones that I am particularly interested in are O, KA and Mystere.

Needsun,
Check out www.smartervegas.com for a list of discounted shows. Right now they have Ka for certain dates at %50 off. On many occasions I have also seen Mystere discounted at %35 off on that site.
There are also several half price ticket booths in Las Vegas. When I was there last May they were offering Mystere at a discount but this is no guarantee, as you have to wait until the day of the performance in order to see if they have any tickets available. Good luck and have a great trip!