A bazaar has an advantage over adding goods to the item market since a bazaar allows you to buy multiple quantities of a single item at once, has limit to how much you can put in it and doesn't charge the 3% listing fee that the item market does, allowing for faster and more convenient sales, with better profit margins.
A quick way to identify if a player has a bazaar is the flag icon shown under their name in the Forums and the shop stall button on their profile. If the bazaar is empty then the flag icon will not appear alongside the player's name
You can also find out who has the cheapest items via the Item Market. Once you have selected an item, scroll down to see the bazaars which are currently listing the cheapest prices on offer. The most popular bazaars are shown on the front page of the Newspaper (the amount of customers and the amount of items sold determine which bazaars are featured here).
For how to edit Your Bazaar see How to edit your Profile Signature