CSI: The Complete 1st Season Paramount $49.99
(USA version, 6 discs)

CSI: Crime Scene Investigation: The Early Cases (Volume 1) $35.73 (3 discs, episodes 1-12), CA version
Studio de Distribution: Alliance

CSI: Crime Scene Investigation: The Early Cases (Volume 2) $27.99
(3 discs, episodes 13-24), CA version
Studio de Distribution: Alliance

If you like this TV shows and you have enough money, buy USA version.
If you do not have enough money at present time or you always have volume 1 like me, buy ca version in separate.

Different prices, different studio distribution, the same contents.