*******This is mostly for fashion student or graduated ones, BUT if your not and you still kno PLEASE do tell

I just moved here awhile ago, I'm a graduated Fashion student from Paris and I was wondering WHERE ARE ALL THE SUPPLY SHOPS?
Where do you guys go to buy fabrics, finishing and etc? Or where are the best shops (cheapest would be nice).
Usually the school gives you list of where to go and where to buy the cheapest or by in BIG amounts.
Also in Paris you can dumpster dive for fabrics in Sentier (Sentier is where some clothing shops work and around 5pm they throw away a lot of used fabrics, some things are keepers some are really just trash), is there anything like that in Helsinki?
Thanks!!!!