if you want to look for phone cases try www.obeythekorean.net like those two beauties above
For clothing purposes Munkypop or You can try Amazon.com, eBay, etsy or kpopmart which I'll post below. http://munky-pop.theshoppad.com/ https://www.etsy.com/search?q=kpop&order=most_relevant&view_type=gallery&ship_to=US
Albums or other cute kpop merch amazon, ebay, kpop town kpoptown.com
also for people who like live and love YG they have their own us site to buy all yg fan merch from 2ne1 all the way to iKON! http://www.ygeshop.com/m/index.html?