Read my post here:
https://www.ukpunting.com/index.php?topic=5201.0In order to enjoy SK, you'll need to do your homework. The ISG Seoul forum has good material. Up until the mid-2000s, SK was a punter's paradise, now it's a hardship tour (term devised by the USFK stationed there).
There is still fun to be had, on-par with the best in the world...but it's mostly off-limits to non-Koreans. Business colleagues and partners are likely to take you to joints similar to Chinese KTVs if they like you. Costs are anything from $500 to $10,000 for the group depending on how upscale the place is....costs are usually covered by the company card.
Also, be careful where you spend your money....you could spend $70-$200 on an absolute stunner that will fuck your brains out....or you could end up spending upwards of $500 for a troll with a shitty attitude.
Do your homework, speak to experienced folk...you'll be fine.