this is the ssal ddeok (rice cake) i used. fresh tube-shaped rice cakes are preferred when making ddeokbokki whereas the thinly-sliced ones are usually used for making soup.
also, if you reside in singapore and love shopping for korean groceries like i do, you may like to check out harin mart, a korean grocery supplier in singapore. they're not a supermarket but a warehouse located at marsiling industrial estate. i checked it out some weeks ago and the main attraction is that their prices are alot cheaper compared to korean supermarkets like solmart. the rice cakes are $3.80 a 600g pack whereas solmart is selling $6.80, the shin ramyeon is $1.20 per pack and gochugaru (korean chilli powder) is amazingly cheap at 1kg for $12 whereas i used to buy it from solmart at $14 for 200g! they also hv lotsa fresh produce and deliver islandwide, so check it out! and no, i'm not advertising for them, i just think no one should pay for overpriced korean groceries from now on :p
recipe for the ddeokbokki can be found here.