I have a Samsung phone with all the accessories for sale. It is 6 months old and was used with SHOW cellular in Korea. It's in excellent condition and has a lot of features. It has 2 cameras. 1 is a 1.3 megapixel on the back and the other one is on the other side for video calling. It has a sim card, a slot for a microSD card and is bluetooth accessible. It also has a data cable, charger, adapter, 2 batteries and a clear hard case.
You can easily get a number for this phone if you have a passport. A SHOW contract is 30,000 won to sign up and outgoing minutes come in 10,000 won increments. All incoming calls are free, of course.
So there you go 70,000(cost of the phone) + 30,000 registration fee (If you use SHOW. I'm not sure what other providers charge) + 10,000 won(for outgoing minutes) = 110,000, and your making calls here in the ROK. The stores in Itaewon sell crappy used cell phones for 100,000 and have sky high prices for their pre-paid plans. This is probably your best bet if you need a pre-paid phone now.
Send me a message and I may be able to meet you in or around Seoul on the weekend.