Not all Korean are able to speak English, including the shopkeepers and food sellers in Korea. The more you can communicate with them, the more kind they will be to you. Don't worry, they will not judge you about your pronunciation, just be friendly, they might give you large discount or extra gifts.
Here, I post some of Korean useful simple phrases that you can use when you're travelling in Korea, especially when buying foods and shopping. Below here is the video tutorial, completed with the simplified pronunciation and speaking tutorial with my own voice.
