What is this browsing you speak of?
Note in the real medieval period you could not browse a shop. You were not even allowed in the shop most of the time: too much risk of theft. There was a window with a counter and you told the shop owner what you wanted and they brought it to you. That did not change until very recently. That is why smaller shops had half doors (Dutch doors): you would open the top but leave the bottom shut, thus doing business but not letting people inside. Larger shops had a purpose built window with a shutter. Many people lived in their shops as well, so there is even less reason they wanted to let you in the shop. You characters will not be allowed in a shop without a good reasons, such as a cobbler's or tailor's that needs to take measurements. This depends on what level of realism you want, but it can also help player to get into the mindset of a setting where the craftspeople are the people selling their goods.
A shop only selling one thing is fine.
Shops also tended to be very specialized, and many things were made to order. A shop may only sell paper, and nothing else. It may have many kinds of paper, but it is completely believable for paper to be the only thing they sell. A dialog would go along the following lines:
"What does this shops sell?"
"Candles." The shopkeeper points to a carved candle over the door.
"Just candles?"
"I have big candles, small candles, tall candles, even scented candles that smell like flowers. It's a candleshop. I'm a chandler, if you want boots go see a cobbler."
Smaller towns might not even have many types of merchants, relying instead on traveling merchants for many goods.
Hand them a list of shops
All you really need is a list of shops and maybe a brief description of what they sell (not everyone will know what a cobbler is). This list would be roughly the same for any city that size, although you can create some unique shopkeepers to add flavor or cross out a random shop ("Eaten by wolves, very sad"). You could literally just hand this list to a player — that will let them scan it for ideas instead of you basically reading the same list. Then they can decide which shop they actually want to go to. If you want to narrate this, most shops had a carved sign to identify what they sell, and the list could represent the characters scanning all the signs as they walk along, which they can do while walking and talking or even while just doing other things around town.
You can give almost every single item on the equipment list its own shop in a large city. The rich actually hired stewards to handle all the day-to-day shopping for them. For this reason (among others), the stewards' job was to know where every merchant was and buy things when needed. If you want a master list for the players, there is an old book, Gary Gygax's World Builder, which is nothing but list and lists of mundane objects. Lord Eadric's master equipment list is good as well, even if it is for an older edition.
At best there might be a seasonal or permanent marketplace with stalls; each seller would not have much variety though, but at least they would be mostly in the same place. That's where you pull out the "lots of foodstuffs, some animals skins, a few animals, but one stall catches your eye..." general narration. Chaotic shiny actually has a nice generator for bazaars/markets you can use to bulk out your list quickly. I myself have a random mundane useful item list I made just for random stuff players might find in defeated NPC's pockets — things like a collapsable leather bucket, a jar of grease, or a stuffed mouse. Any time the players think of something we add it to the list; it helps make the fallen feel real but could just as easily be used to flavor up a market or bazaar.
The one exception to the one shop per item was pawn shops, which had such diverse merchandise they had to let people see it, but even then it was separated by a counter. You could easily create a spreadsheet or chart for pawnshops. The various magical shop inventories you find might be a good example of what a pawn shop might look like, where most of the merchandise is unique. Donjon's shop generator is good for this one.
This is balancing narration and information — there is such a thing as too much narration. Do I take several minutes to try to describe the location of every character every time anyone moves, or do I use a map grid? Do I describe the puzzle in minute detail or do I hand the players a sketch of it? If the player wants a list of everything, then give them a list. A simple physical list is far faster for browsing than taking several hours to narrate every shop in a city, and better reflects how browsing happens.
