Getting a prepaid phone

I posted last week that I will be getting a UMPC and a cellphone in time for school. South Korea’s population is about 48 million and more than 40 million owns a cellphone (휴대폰 hyu-dae-pon, 핸드폰 haen-d-pon) and I belong to that 8 million people, mostly children (?), who don’t own one.
[singlepic=575,250,250,left]I could’ve gotten a phone earlier but I didn’t think it was necessary then. Since I’ll be going to school this fall, my husband suggested that I get a phone. I’ve been searching since Monday and I’ve decided to go to the prepaid route. I can get a new phone for free (공짜폰 kong-jja-pon) with a 12-month plan. I wanted to get the “Mini skirt” phone from Samsung but I really just need one for calls and SMS. The subway map would come in handy but I surprise even Koreans with my “navigation” skills when it comes to Seoul. So basically I’m looking for a phone that will allow me to make calls and send/receive SMS and has a dictionary.
If I decide to get the “Mini skirt” phone plan, I’d have to pay 1 won for the unit, 30,000 won (US$30) for registration and a basic monthly charge of 14,000 won (US$14) with calls charged at 18 won per 10 seconds. I won’t need to pay for calls received, unlike in the US.
With a prepaid phone (선불폰 seon-bul-pon), I can get an old second-hand phone for free and an initial charge of 20,000 won (US$20). There’s a monthly connection charge of 4,500 won (US$4.50). (To cover the cost of admin jobs). A call is 33 won/10 seconds and 20 won (US$ 0.02) for SMS. Luckily, a used phone that has a dictionary is available at the store I went to. I will just need to pay 20,000 won (US$20) for it since it’s newish (2007 model). I’m delaying to get a phone until the third week of July.
Even tourists in Korea can get a prepaid phone. However, it would be disconnected after 90 days unless an ARC (alien registration card) is presented. I should’ve known about this when Tesha and Angela were here.