In Alabama, buying a house authorize you to leave your apartment with 30 days notice?

Welcome to AMHD; probably not; you will need to review your lease.

If you have a lease, almost never, if you had that clause written into your lease, but you are bound by the terms of your lease, I have not seen any that allows you out for buying a house

If you can't afford one move in with family, get a job, and wait until you can.

There are other threads that have discussed this. No state has a law that allows one to break a lease because they are purchasing a house.

So you have 3 options:

1) negotiate a buyout with the landlord
2) sublet
3) find a replacement tenant

The one thing in your favor is that the landlord is required to make a good faith effort to re-rent the unit. And they cannot double dip. Maning as soon as they have a new tenant your obligation ends.