I have a SIM card and I'm with koodo, if I bought an unlocked blackberry, would my sim work with this phone?

would bbm work on this unlocked blackberry ?

Yes, it will work. Only locked phones need to be unlocked to swap simcards. Recently, I suffered from such a locked phone and then using the permanent unlock solution from Mobileunlockslutions.com I was able to unlock and swap simcards easily.