I read this forty plus years ago in the UK. It was a lot of short stories, a chapter to each story, or it could have been a fix-up book. There are only two I remember so I'll describe them both, it's the book that I'm after, NOT the individual story titles (although that would be nice if someone knows)
Story A: The two are off on a voyage to move some freight to a planet, once they're in hyperspace they'll be in it for a few weeks.
The pilot does the jump and then it gets to mealtime, he is horrified to see they have no food in the galley. His partner leads him to a big metal box and explains it's alien tech and can replicate any meal you can think of. They happily eat and then sleep.
The next day there are problems and it won't provide any food, after tests with it producing a yellow pencil but then not a red pencil the pilot realises it only produces one of each class of items. He thinks for a second and says "roast chicken" and one appears. Then he says "Damn, I should have said turkey". At the story end they reach a spaceport near starved. They've eaten things like insect cake and (because the machine couldn't categorise it) duck billed platypus
Story B: The partner arrives with another alien tech device, a ( I can't recall the real name) Whatsit free producer. This has instructions on the side which, when translated, explain how to start it, together with a warning that it takes a "thingummy" key to stop it. He presses the start and a grey dust rushes out of a slot and begins piling up and filling their spaceport office shack.
They analyse it and learn it's used as a cheap construction filler and can be used as the base for synthetic food production on one planet. They are soon getting it trucked away daily and just breaking even but their power bill arrives and it's massive. They learn the machine draws power from around it and is costing them a fortune.
They load it up and fly off to the food production planet, they arrive with their ship's power seriously deleted, they trudge through dust to a customs hut and proudly declare that they've brought a Whatsit free producer, the customs man turns hostile and tells them to get off his planet and to take their damn free producer with them.
They realise the dust on the landing field and the hazy atmosphere is all the same grey dust.
As they leave the customs man tells them that if ever they get a "thingummy" key they can name their price