The ship's store was a location aboard Federation starships set aside for items usually not carried in the cargo bays. Such items included apparel, tools, and samples of compounds. On a Galaxy-class starship, ship's stores were located on deck four.
In 2266, aboard the USS Enterprise, Charles Evans gave a gift of perfume to Yeoman Janice Rand. The ship's stores didn't stock that kind of perfume, so Rand asked Evans where he had obtained it, but he gave her no answer and she left him in a hurry to attend to her duties. (TOS: "Charlie X")
Later that year, upon contacting the Enterprise while stranded in command of a landing party on planet Alfa 177, Hikaru Sulu was surprised that the member of the crew who answered was none other than the starship's commanding officer, Captain James T. Kirk. He humorously replied that he was "watching the store," having given everyone else the afternoon off. (TOS: "The Enemy Within")
The next year, Kirk again referred to the Enterprise's store, immediately after Doctor Leonard McCoy remarked that Spock reacting uncharacteristically overjoyed at finding that Kirk was still alive had been logical "in a pig's eye." To McCoy's comment, Kirk, momentarily turning back as he and Spock were about to leave sickbay, suggested they "go mind the store." (TOS: "Amok Time")
In early 2364, aboard the USS Enterprise-D, Lieutenant Natasha Yar went to ship's stores for sexy sleepwear. She was later seen in this sleepwear when seducing Lieutenant Commander Data. (TNG: "The Naked Now")
Later that year, Lore retrieved a macrotool and samples of quadratanium from the Enterprise-D store. With his possessions, Lore knocked out his brother Data with a combination of champagne and quadratanium, and repaired his face with the macrotool. He turned the tool on Data, causing damage to his face. (TNG: "Datalore")
A ship's store was also located on the Promenade of Deep Space 9. This store specialized in selling and repairing starship components. During the Occupation of Bajor, it was the site of a chemist's shop. (DS9: "Necessary Evil")