once you see the cost you wont need it.
I disagree . . . . yes, there is an initial cost involved, but the plexiglass will last for many years.
I have one 4x8' white sheet that has been used for over a hundred shoots. I lay it down over portion of the white seamless that is on the floor to protect the paper, as well as provide a pleasing, very slight, reflection.
This is one of those items that I would recommend to every studio photographer. It's well worth the investment.
Here is an example from a recent catalog shoot of what the plexi looks like on a white seamless . . .