Learn Turkish: Kalabalık kelepir ayakkabıları çılgınca kapışmıştı. - The crowd had wildly snatched up the bargain shoes.

The base verb kapmak means to snatch or to grab. Adding the reciprocal suffix -ış creates kapışmak, which describes a group of people eagerly scrambling to grab something for themselves, competing with each other. It perfectly captures the chaos of a crowd fighting over a bargain.

Since this lesson is about the chaotic -An ... -(y)A structure, could we use that here instead?

Yes! To emphasize the sheer chaos, you could say Kelepir ayakkabılarda kapan kapanaydı (It was a free-for-all of people grabbing the bargain shoes). The verb kapışmak gives a very similar chaotic, competitive feeling but allows you to keep Kalabalık (The crowd) as the standard grammatical subject.

Is kelepir an adjective or a noun here?

Kelepir essentially means a bargain or a steal as a noun, but it frequently acts directly as an adjective in Turkish to describe extremely cheap, discounted goods. Here, it acts as an adjective describing ayakkabıları (the shoes).

How does the -ca suffix work in çılgınca?

The base word çılgın is an adjective meaning crazy or wild. Adding the -ca (or -ce) suffix turns it into an adverb, meaning wildly or crazily, which modifies the verb to show exactly how the crowd was snatching up the shoes.