I bought one off Amazon for a few bucks called "Accessory Export Phone Effects Screen Protector." US$4.99 for a 3-pack. I have a tiny bubble on the edge near the LED, but otherwise it is effectively invisible. I think it is a little more reflective than the original glass, but I think it is fine. For that price, it was worth a try.

Looking at it now, I see a small scratch on the protector...glad I have it on there!