Besides the black ticekt there are daily revivals to help you start the game
These give you shitload of SC so you can get the 150 SC stamp in the first two months (giving another premium 2 blacks on average) and they are really generous with SC in general so after that you should get 4-5 premium blacks / year even as FTP.

Also you don't have to bother levelling silver units; unit roles you lack you can get directly from the revivals or TP (which rotates much more frequent)