Actually Lexan/Plexi is not much cheaper.
My quote for rounded corner size of TEMPERED GLASS was $44 something locally.
While a 2x4 sheet of 1/4" for Plexi at Home Depot/Lowes/Menards costs $28. That was just cheap 5x strength Plexi. 10x Lexan will cost more
You need to then buy a plexi cutter for a few bucks, have a good level/straight edge to trim 2" off one side and 16" off the other side. Then you have to figure out how to cut the corners correctly. Once you do all that, then you have to figure out how to slightly round the edges and sand it.
TRUST me... I did this for a friend... It took me over 5 hours of working with the plexi with wood planers/sanding blocks and stuff to get it even close to what looked okay. The edges turned out really nice, but not perfect. The corners were quite bad but luckily it went on an Atari cocktail not a midway one, so the corners were 80% covered by the retaining clips, hiding my awful curves.
Then, to top it off, the surface is VERY scratchable. Yeah you can buff out light scratches with Novus polish but once a good gouge is in it, it's there to stay.
I wish I had convinced him and myself to "just spend" the extra $16 for a solid piece of tempered glass. The work was not worth it in the long run to make it look good.
Now if you're talking a front bezel for an upright that is entirely sealed by the edges so no sanding/rounding/curve cutting is needed... Plexi is a great product (and there you wont need 1/4" either). Just cut one or two long edges (~10-15 minutes work) and you're done.