Although shop assistants wear name tags, they will never use their given name to introduce themselves. You will never have someone say “Hi, Please call me Sam” to you in Korea, even though this might be appropriate in Australia.
Depending on the shop, the shop assistant will use ‘손님 (son-nim = customer)’ or‘고객 님 (go-gaek-nim = distinguished customer)’ for you, or sometimes a kinship term. For example, a young clerk at the bank may address a customer with the polite and neutral term ‘선생님 (seon-saeng-nim = Mr/Ms/Teacher)’ or ‘고객 님 (go-gaek-nim = Dear customer)’.
In the market, for young girls, they might use ‘언니 (eonni)’, for middle aged women ‘아줌마 (ajumma)’, and for middle aged men (and maybe younger men too) ‘아저씨 (ajeosshi)'. Elderly customers are referred to as ‘할아버지 (harabeoji)’ for men and ‘할머니 (halmeoni)’ for women.
If you need to call out to a staff member to attract their attention, the term you use depends on the type of business. If you are at a café or restaurant, you can use a kinship term, for example to a young female waitress using "eonni" (literally older sister) if you are a female, but usually people don't use any term but simple say "여기요 (yeogiyo)" (literally over here!) to catch their attention. If you are in a shop, you can use kinship terms as described above (i.e. eonni, ajumma, ajeossi, harabeoji, halmeoni, etc.).
Want a better view? Download this note :