I'm gonna get a minecraft pc game card and is there a way i can play offline?

Once you've downloaded the client to your PC minecraft can be played offline.

Once Minecraft has been downloaded and installed, you may play it offline as much as you want. Though there are some obvious restrictions when it comes to playing without internet: Multiplayer is impossible, and updates will not occur even if set to automatic. If you are willing to deal with these obvious faults, then yes. Minecraft can be played in it's entirety once it has been purchased, downloaded, and installed and you have the appropriate Java version.