TWL is on the right track. In the price range you're looking I'm not sure you'll get an improvement as much as a difference. Power line conditioners, especially inexpensive ones are as likely to get in the way as not. I don't know if it's a need but I'd suggest making a few power cords with the $150. You can make out like a bandit by throwing together a few cords from the audioasylum site.
Good luck!
Good luck!