Cheap and Expensive
Cheap and expensive in the shop
Some goods are cheap, 'goedkoop' and some are expensive, 'duur'. If we go out shopping, 'als we boodschappen doen' do we usually carefully look at the price, 'kijken we nauwkeurig naar de prijs'. 'Boodschappen' in this sense are usually used in the plural ('in het meervoud'), while the standard meaning of 'boodschap' in the singular ('in het enkelvoud') is 'message'. An official of a lottery could phone you with the nice message that you have won an expensive car: 'Ik heb een leuke boodschap voor u, u hebt een dure auto gewonnen! What we buy often, 'vaak kopen' include provisions, 'levensmiddelen' such as milk and bread, 'melk en brood', clothes, 'kleding' or 'kleren', paper, 'papier' and petrol, 'benzine'. If we visit a shop, 'winkel' or supermarket: 'supermarket', we are welcomed there as 'customers', 'klanten'. For most of these goods most customers are price-conscious, 'prijsbewust'. They are keen on high prices, 'hoge prijzen' versus low prices, 'lage prijzen', and particularly in price cuts, 'prijsverlagingen'. Sometimes a price can be low enough to speak of a bargain, 'een koopje'. A more straightforward expression is 'dirt-cheap', 'spotgoedkoop', where 'spot' as a noun means 'mockery'. Really derogative is the use of both 'cheap' and 'goedkoop' to disqualify an utterance, 'uitspraak', e.g. a cheap joke, 'een goedkope grap'.
Purchase and sale
The equivalents of purchase and sale are 'inkoop' and 'verkoop '. Again 'koop' is used to make compound words, a construction which appears more often in Dutch than in English. 'Inkoop' is what a shop owner, 'winkelier' does, buying a large supply of an article at a low price, 'een lage prijs' and 'verkoop' is selling it at a higher price, 'een hogere prijs'.
What the words really mean
The terms cheap and expensive, 'goedkoop' and 'duur' originally meant something else. Few speakers of English realize that cheap is nothing else than 'buy', what 'koop' expresses in Dutch; 'cheap' and 'koop' have the same origin. It is by origin a Germanic word. It is quite funny that expensive, based on a Latin word, similarly means something you buy, 'iets dat je koopt'. Still more interesting is that there is a synonym, 'dear' which is clearly an equivalent of 'duur', but it is used rather as 'precious', 'kostbaar', but basically it means expensive. Literally, the Dutch word 'goedkoop' does not mean cheap at all, but 'a good purchase', 'een goede koop', and most probably the original meaning of cheap was the same!
Finally the word 'duur' is a very interesting complex term. Its trivial meaning is 'costing much money', 'kost veel geld'. At the same time it is the basis of 'duurzaam'. English has the similar word 'durable'. And what about 'duration', continuation in time. The Dutch word is again 'duur'! The related Dutch verb is 'duren' and if something takes a long time, the Dutch say: 'dat duurt lang'. That 'dear', 'dierbaar' has the same roots is interesting, but that is worth a separate blog post.
'Goedkoop is duurkoop' or rather 'duurkoop is goedkoop'
'The expression 'goedkoop is duurkoop' has the English equivalent 'quality pays'. Something cheap may appear to be not durable and buying another item makes the purchase expensive after all. The Dutch word 'duurkoop' is mainly used in this expression.
Now, since 'goedkoop' properly means 'een goede koop' en 'duurkoop' properly refers to a durable article, it is completely in order to reverse the words and speak of 'duurkoop is goedkoop' And the English equivalent would be 'quality lasts'.