Those cheap plastic ones just don't last very long.
And the concrete ones are quite cumbersome.
If I ever meet a Polish frying pan salesman, I will be delighted. This sentence is in nearly all my practice lessons!
what's the issue with
I am selling a metallic pan
OK, seems like this can also be used. Added.
Why does it need article?
Well, in most cases an English sentence without an article before a noun would be incorrect English.
As Jellei said, an article is usually needed before a noun - but only in the singular form. "I am selling a metal frying pan" or if it were plural, "I am selling metal frying pans".
Thank you friends!