I have some pointers. I used to live int Turku. Komponenttipiste was my favourite place, untill they changed completely to post-order. Elfa has one dealer in Turku (by Aurajoki), but it is probably the most expensive one. Triopak is a good place, I have been there. They have all the standard components and some shelves which you can browse.
If you don't mind ordering by mail, I recommend partco (main site: partco.fi, webshop: partco.biz). It is now my favourite place here in Espoo, decent prices, a huge selection and has given me a nice overall experience (can order farnell's stuff too!). I used to order lager orders from there when I lived in Turku
Oh, and there is no Bebek in Turku.