Can any one tell me how many migration tickets you need for a base lvl 25 with 12m power?

I don't know the number of tickets myself, but it will depend on your relative power (ranking position) in the state you want to move to.

One option to save tickets / money is to allow your troops to be killed before you move. This will likely drop your power considerably. You would then train more troops when you arrive in the new state.