Hi there!! so personally I purchased from www.twowaymirrors.com due to the fact that no glass companies in my area sold one way mirror/two way glass (they are the same thing, i get that mixed up frequently!) But call around to local glass shops and see!
I personally recommend the glass and not purchasing the acrylic as it is a small price difference for a huge change in the quality, acrylic tends to look less relfective and doesn’t look as natural as the real glass does. I have never used plexiglass so I can not speak to its quality. The real glass looks like a true mirror even more so in my opinion than the “Smart mirror glass” but to each their own! Best of luck i hope this helped answer your question a bit!