Is it reliable to go to Korea for five days by boat 1500 yuan?

I'm going to Jeju Island Autonomous Region in South Korea. The places you are restricted to are too official. Generally, Korean folk art is the most valuable, but they will only take you to the most expensive and unpalatable restaurants. Anyway, don't believe it. If you go to Korea, it will cost about 4000 yuan in 7 days. Generally speaking, you can only get a tourist visa for seven days unless your relatives are there. ...