Google "used theater seating" ... there are several sites that sell good used theater chairs.
Make sure you ask the salesman, "is there any damage, what-so-ever, to the chairs? Rips? Tears? Rust? Cracks?
Don't be scared if the chairs need a good cleaning. Used movie theater chairs clean up fantastic with a steam cleaning, or a upholstery cleaning machine. Think about it, the dirt on a theater chair, coke, butter, is exactly what the upholstery detergent in a upholstery cleaning machine is formulated to clean. Some chairs (I.E. Irwin Marquees and Citations) can even have their seat bottom cushion covers removed and put in the clothes washing machine!
Do not buy junk! You get what you pay for :-)