I think Bose is having a sale this month (November) where everything is 10% off. Helps a bit but they are still spendy. I use a couple of 15" active speakers, a Carvin mixer, BBE Sonic Stomp, a couple of fx pedals and an old fashioned cd player to run the backing tracks. Everything goes thru the mixer. I recently added a Harmony G vocal harmonizer to the list. That is a kick in the pants to play with, but I wouldn't try it live on untested songs. It ain't perfect yet. Maybe the newer XT version is better, but if you know it works on a song it really adds something to the final product.
Good luck and have fun.