I tried to spend a 1000 won note I had in my pocket today. Looked like a $5 bill.
Compare:
http://www.banknoteworld.com/banknotes/korea_south/KoreaSouthPNew-1000Won-(2007)-donatedfvt_f.jpg http://www.pokeraddict.net.au/userimages/user3148_1168313835.jpg You can see my confusion. The woman at Wendy's picked it right out and was like "what the hell is this!"