You shouldn't need more than a class 6 for a 550D since their FPS burst is relatively slow.
I bought a 16GB class 10 for about 30$ USD
You can check www.digitalrev.com they ship internationally.
The class10 card is for the video's..not the images A class 4 card would probably be more than good enough for pictures etc.
HD-video requires faster transfer-rates though.. And that's why I need one.
30$ for a Class10 card sounds extremely cheap