Last year, I had a festival gig in which I neede to provide a live sound system with enough power for 300 - 500 people in an outside crowd. My regular bass player recommended Guitar works as having quality systems available for rental at a fair price.
I provided the mikes and monitor speakers for the stage. They provided 4 great speakers, a powered mixer and all the mike stands and cords I needed for well under $100. The system worked great. It's a lot easier to rent what I need at under $100 a pop as opposed to laying out a couple of grand for a mixer and speakers.
Their owner, Terry was great to deal with, and the staff did agreat job of going through the connections and set up.
I recommend them highly as a source for rented sound systems.