use Western Union next day service.
It only cost $14 service charge upto $1,000 wire transfer. Even if it says next day, it does take only a few hours.
The only catch is that your parent has to go to Kookmin Bank to collect the money. Western Union will give you a transaction number and you can let your parent knows what it is.
You have to go to a Western Union branch to get this $14 service, not through their website. They usually located in the grocery store. hope this helps.
