On Alibaba, 50 cents.
On Amazon, maybe 1.5 USD.
In the airport, 35 USD. This was back in about 2015.
I did not buy it, and got by as best I could.
Such extraordinary prices materially impact the experience of traveling. To my eye, they seem shortsighted.
I also finally realised some years ago all the "duty free" shops are a giant con.
Yes, they are duty free - but they're all charging about twice the high-street price.
I never buy in airports, which can inconvenient, and it is always unpleasant to witness when I travel. If I were running an airport, I would look to make the experience of travelers as pleasant as possible, rather than actually making it unpleasant.