Chris, the lowest price I have found is definitely departing from Korea. The fare before taxes for a 6 continent Oneworld is KRW5901800 (approx USD 5323.00). The next lowest is South Africa at ZAR37800 (USD 5613.00). India is INR264240 (USD 6054.00) and Thailand is THB286760 (USD7551.00).

As far as taxes go, none of the above countries have a value added tax that is charged to you based on fare paid. The only taxes incurred will be the ones you encounter in each city you travel through.

I do recomment purchasing your ticket in either the USA or Canada or the country of origin (depending on exchange rates). There is a rule that tickets purchased in US or Canada do not have to be raised to the minimum fare of the country of purchase. This is not so for other countries.

Hope this helps you. And have a wonderful trip.