For the cost and quality, a JBL PA system should do the trick. They have many models,
Things to think about: does the venue need a powered mixer or unpowered? JBL mostly makes powered speakers- there are pros and cons to both.
Buying powered speakers and an unpowered mixer (for instance, purchasing some QSC HPR powered speakers with an unpowered mixer) could save money by not having to purchase a power amplifier to power those speakers.
Your friendly neighborhood music shop should be able to help with the specifics; these points are meant to be a starting point in the conversation....
Hope it helps!