From what I tried finding from travellers I know who have been to South Korea, the trip is possible between 40K to 60K per person. Kindly check with travel houses who might help you better with the trip and the package. You can check with Thomas cook, SOTC, MMT and Yatra.
The average price of a 7-day trip to Seoul is $1,705 for a solo traveler, $3,062 for a couple, and $5,741 for a family of 4. Seoul hotels range from $47 to $201 per night with an average of $58, while most vacation rentals will cost $130 to $340 per night for the entire home