I did rotation at a previous church and secured seats for nothing. This involved lots of lurking around an "adult" theatre that was closing and being re-habed as a dinner club. I eventually got some old seats and had them cleaned and sanitized (ahem..) and they were fine. They repented and turned to God!!
You could always ask at a theatre, maybe they would have some old seats stored somewhere-or they could tell you when they are going to update their facility- you never know.
Hope everyone has a very Merry Christmas!!