Learn Polish: Wolę kupować produkty wegańskie. - I prefer to buy vegan products.

The verb woleć (to prefer) can be followed directly by an infinitive when you are talking about an action you prefer to do. Just like in English, you use the conjugated verb for "I prefer" (wolę) and the infinitive for "to buy" (kupować).

Why use the imperfective verb kupować instead of the perfective kupić?

Because this sentence describes a general habit or lifestyle choice. You use the imperfective kupować for ongoing or repeated actions. You would use the perfective kupić if you were talking about completing a specific, one-time purchase.

What case is used for produkty wegańskie?

It is in the Accusative case because it is the direct object of the verb kupować (the thing being bought). For non-human plural nouns like produkty, the Accusative case looks exactly the same as the Nominative (basic dictionary) case.

Why is the adjective wegańskie placed after the noun produkty?

In Polish, adjectives that define a specific category or type of something usually go after the noun. Since being vegan classifies the type of product, we say produkty wegańskie rather than putting the adjective first.