You can register with some of the bird rehoming charities, birdline, charge a yearly membership etc, but so many birds on there, also preloved, gumtree sadly have lots of scammers on their pet sections and are best to be avoided, also if you are on facebook, there are several bird pages on there for buying and selling, there is a guy i know named stuart who breeds Galah's, not sure if he has any at the mo but i can ask for you x