Please identify if this is valuable medal.
Yellow ribbon with 3 edge stripes is the South Korean Order of Civil Merit (국민훈장國民勳章) Class 3 (Dongbaeg Medal), the current version awarded since 1973.
The Order of Civil Merit, Dongbaeg medal is common. If it has a production number on the reverse, it dates from 1973 to 1984 and there were 1,905 issued. If there is no production number, then it dates from 1984 to present and there have been 31,789 issued as of Sept. 30, 2023.
The 1st and 4th medals are Korean Youth League awards and are a little harder to acquire (but nowhere near the significance of the orders). I have written about these on my website at https://koreanmedals.com/korea-youth-league/. I have no information on how many were issued. It looks like they have blue center medallions, which would indicate High School level awards. I would need good clean pictures of the reverse to add some more information.
The third medal from the left is a boy scout. The reverse probably has 봉사장 or Service Medal. These are not difficult to acquire.