While the websites mentioned before would also be helpful for those living in Busan since many of them deliver to Busan, it might seem difficult to find the same amount of stores in Busan that can provide baby equipment like those in Seoul. However, there is still plenty to go through including major department stores like Lotte Department store. You can look in the markets within the department stores or places like E-Mart. To find more economical prices, try going outside these major chain stores and check out places Busan’s Premium Outlets, Gukje Market, Choryang Arcade, and Busanjin Market. They tend to be less expensive and provide more discounts for their customers.
There are also neighborhood markets that you can find. While being on the smaller side, they tend to pack in a lot of stuff and sometimes can even order in items for you. If you have someone with you who speaks Korean then ask them if they can accompany since many of these shop owners will be older and less likely to speak English.