NASA has a list of approved eclipse glasses: https://eclipse2017.nasa.gov/safety

I ordered some a couple weeks ago; but it took quite a bit of effort to find the legit offerings on Amazon. Just because the Amazon listing says it is made by a certain manufacturer doesn't mean that it's not phony, and Amazon doesn't verify that stuff.

Ordering directly from the manufacturers wasn't an option, either, because most of them wanted $13 in shipping for $10 worth of glasses.