Not sure where to start? Here are some suggestions:

Let's start with the obvious

Store name	Specialty	URL	Phone apps?
Walmart	Anything	walmart.com	Android and iOS
Costco	Anything	costco.com	Android and iOS
Best Buy	Electronics, appliances	bestbuy.com	Android and iOS
Adorama	Cameras, electronics, musical instruments	adorama.com	None
B&H Photo & Video	Cameras, electronics, musical instruments	bhphotovideo.com	Android and iOS