Learn Dutch: De winkel is niet duur en de jas is goedkoop. - The shop is not expensive and the coat is cheap.

We use geen to negate nouns (people, places, or things). Here, we are negating the word duur (expensive). Because duur is an adjective (a describing word) rather than a noun, we must use niet (not) instead of geen.

Could I use geen if I changed the sentence to say 'It is not an expensive shop'?

Yes! If you change the sentence to focus on the noun, you would use geen. You would say Het is geen dure winkel (It is not an expensive shop). Because winkel (shop) is a noun, geen is the correct choice for that phrasing.

Is there a trick to remembering the word goedkoop (cheap)?

Yes! If you break it apart, goed means good and koop means buy or purchase. So, something that is goedkoop is literally a good buy, which makes it cheap.

Why isn't the word order swapped in the second half of the sentence after en?

The word en (and) is a connecting word that just glues two normal sentences together without messing up their word order. Both de winkel is niet duur and de jas is goedkoop get to keep their standard subject-verb order.