From Nookipedia, the Animal Crossing wiki
Clothes are a major category of items in the Animal Crossing series, as well as a huge part of the game. Like furniture, clothes are available from a variety of sources. In Animal Crossing, clothes are most commonly purchased at Tom Nook's Store while in Animal Crossing: Wild World and Animal Crossing: City Folk clothes may only be found at the Able Sisters' shop. Some special clothes are also available via holidays and events such as Gracie's visits in Animal Crossing or New Year's in City Folk. In City Folk, some clothing articles are only obtainable from GracieGrace at very high prices or from the Tom Nook Point System.
Prior to Animal Crossing: Wild World, clothes were the only means of customizing one's character, other than the unchangeable face generated when the player first creates his or her character. The shirt/dress design would therefore also appear on the character's hat. Animal Crossing: Wild World and Animal Crossing: City Folk introduce hats and accessories, making clothing only one of several ways to change the appearance of one's character.
In all Animal Crossing series games, players are able to create custom designs through the Able Sisters' shop by asking Mabel for a price of 350 Bells per design made. In Animal Crossing: New Leaf, players can now make prodesigns for 500 bells by talking to Mabel. Designs can then be used as the characters' clothes and sometimes villagers in the town will wear the clothes and give the player feedback on the design. The original designs in the shop are made by various people from the town called Treehut.
Another way to get designs is to help Wendell by giving him some food. He gives players a different design depending on what type of food he receives.
In Animal Crossing: Wild World and Animal Crossing: City Folk, players can buy clothes at the Able Sisters' shop. Each day there are 2 accessories (facial items or hats), 4 shirts, and 1 parasol or umbrella available for purchase.
In Animal Crossing: New Leaf, Pants, Socks, and Shoes are now customizable, having 2-4 new designs. Pants have three designs, being Long pants, Shorts, and skirts. Socks have long and short socks, and shoes have Sandals, Sneakers, Boots, and Long Boots. Shirts also have three new designs, being sleeveless, short sleeves, and long sleeves.
Animal Crossing: New Leaf has given Able Sisters a whole new design, having the main room with Mabel and Sable have three shirts and two pairs of pants. There is a smaller room connected to the right, where Labelle now works, which has three hats/headgear, three accessories, and one umbrella.
Next store, a short while after players create a new saved town, a shoe store on the steps of an abandoned building called Kicks is built. Kicks is run by an Australian skunk called Kicks, who cleans shoes in Animal Crossing: City Folk for 500 Bells. In there, he sells four pairs of shoes and two pairs of socks.