There is a store selling 505 1 1 17 Yuan Qi balloons next to Carrefour in Faming Square, Xiamen. If it's big, find a gas company.

For example: Xiamen Air Separation Special Gas Industry Co., Ltd. (Xiamen Tongan Chengnan Industrial Zone 0592-7369095)

You can have as much as you want.

If it's just a piece of cake,

Find a wedding company, they all have a one-stop service to arrange weddings.

Such as: Xiamen Huixin Industry and Trade Co., Ltd.

They supply balloons and sell imported helium for holiday decoration (0592-5600198, 4th floor, Sunshine Industry Building, No.29 Xinglong Road, Huli District, Xiamen)/question/8550545.html.