There are several online stores which offer baby monkeys, such as Primatestore.com and Pets4you.com. It would be unusual to find a baby monkey for sale in a traditional store, as they are unique animals that require costly general maintenance.
The decision to buy a monkey should not be made lightly. Monkeys are a giant investment of both time and money. Some monkeys can live for up to 40 years. They cost around $7,000 to $8,000 to purchase, but proper care and feeding will require the owner to spend an additional $50,000 to $60,000 over the course of the monkey's lifetime. Since monkeys are rather intelligent, they can be also be unpredictable and are sensitive to meeting new people.