A list of the locations to find all four Magic Bottles available in The Legend of Zelda: A Link to the Past.
List of Magic Bottle Locations
1. Purchase from the Magic Bottle Salesman: In Kakariko Village in southwest Hyrule, there is a salesman to the west of the weather vane who will sell you a Magic Bottle.
2. In a Chest in a Hidden Room in Kakariko Village: You can enter a secret door in the back of the house south of the house with the sick kid in Kakariko Village. Open the chest in the secret room there to find a Magic Bottle.
3. Under the Bridge North of Lake Hylia: After you get the Pendant of Courage from the Eastern Palace, the Pegasus Boots from Sahasrahla, the Power Gloves from the Desert Palace, and the Flippers in Zora's Domain in the northeast of Hyrule, you can go to Lake Hylia in southeastern Hyrule and swim north along the waterway to reach a bridge. Swim under the bridge and talk to the man there to get a Magic Bottle.
4. In the Locked Treasure Chest in the Dark World: After you get the Titan's Mitt from Thieves' Town in the Dark World, you can reach the ruined house southeast of the Village of Outcasts. Inside, there is a locked treasure chest. Check on it to take it with you, then go south from the ruined house and use the Magic Mirror to return to the Light World. Use the Flute and select location 7, the swamp. Go west to the entrance of the desert and go north to find the man sitting next to the sign. Talk to him and promise not to tell his secret, and he will open the chest, which contains the fourth Magic Bottle.