All great plays written before 1923 (according to Wikipedia) are in the public domain. That’s a lot of plays, most of which are available free on line at Gutenberg.com.
Most modern plays, on the other hand, are still under copyright, and must be purchased.
It’s likely soon we’ll read be cold-reading ebooks, paperless. Until then, regardless of the source, we need copies. Some come from the personal libraries of our readers; others, we scrounge.
On-line used bookstores sell anthologies of four to fifty plays for anywhere from $0.01 plus S&H to $50 (a dollar a play). Photocopies (legal ones) are a nickel a page at the cheapest place I’ve found.
We count on the pocket change of those with pocket change to spare to provide at the very least one script for every character in every French scene, which are passed from reader to reader. To read along, one may bring a personal copy or arrange in advance to reserve one at cost (if available); otherwise, unless a patron magically appears, one listens till ones turn.
Planning Ahead
Copies will be archived somewhere to be read by other groups if this thing catches on.
Any questions?
Comment below.
Cold Reads/International 
People can now express themselves in many ways. Does this signal that plays have a different purpose than expressing one’s views? What then is the purpose of plays?
Thanks, Scott. You’re the first commentator. I’d answer your question, but I’m out the door…
The purpose of plays is to express one’s understanding of human behavior.