I think you can get new, plexiglass ones for about 45 bucks from arcadeshop, but since the original is glass, it would be worth more if it was in good shape.
Not to mention you need to be able to ship it without it getting broken. I shipped a glass bezel awhile back and I went to great pains to make sure it had a good chance of getting there in one big piece. Which it did thank goodness.