Shops sell a variety of things that you might need while you play Argonath. You can use the command /buy to see what a shop sells.
There are several shops which you can buy personal items from. These are called the general stores, and are marked by a diner (pink drink) icon on the map. These shops sell handheld items (e.g. cigars, shovels, basketballs, briefcases), special items (e.g. oxygen cylinders). These items are carried by you in your inventory. There are 2 slots for common items, and 1 slot for personal items. The first two can be managed by the commands /useobj and /dumpobj. The other one can be managed by different commands.
There are also businesses which sell food and drinks. These products will bring your HP up, and if you buy enough of these you can fully recover your health. These are the fast-food restaurants, donut shops, common restaurants, bars, and clubs. All of these sell products which can heal you.
Other important items are the electronics. The electronics stores can sell you those important devices. For example, you need a cellphone to communicate to other players, request services and publish advertisements. From these stores you can also buy a walkie-talkie, which you can use to communicate with friends and a radio player, which you can use to tune into Argonath Radio while in game.
Besides those, other types of shops exist, such as sex shops, clothes stores, and gyms (used to buy new fighting styles).