How can I buy the Lays potato chips Ketchup flavor in Hong Kong?

Unfortunately, I don't have access to real-time information, including product availability in specific locations.

To find out if Lay's Ketchup flavored potato chips are available in Hong Kong, I recommend the following:

1. Check Major Supermarkets: Visit popular supermarket chains like Wellcome, Park'n Shop, AEON, and others. Their online websites may also provide product information.

2. Look at Convenience Stores: Convenience stores like 7-Eleven and Circle K might carry a limited selection of Lay's chips.

3. Search Online Retailers: Check online marketplaces like Taobao, Lazada, and Shopee for options. Be sure to verify the seller's reputation before making a purchase.

4. Contact Lay's Distributor: Try reaching out to the local distributor of Lay's in Hong Kong. You can find their contact information on the official Lay's website or through a web search.

Keep in mind: Product availability can vary depending on the time of year, specific store locations, and demand.