I need help with buying a bird!?

Only cage like birds together. Sometimes different species get along but it is not the norm. Also when getting a new bird you need to take it to an avian vet and quarantine it for at least 30 days but 90 is preferred. That means a separate cage and room. Means changing your clothes when you play with the birds also. That is to protect both birds from diseases. There are no such thing as vaccinations for birds. After the quarantine you can let the birds get to know each other. There is no for sure thing to make them get along either. You might get 2 birds who like each other or hate one another. You also need to know the gender of your bird and the new bird. Two males can get along but 2 females could fight to the death.