Nirvana.com that's where I got my 5 northern lights autoflowering feminized for 39 bucks and they send me 10 free random seeds so a total of 15 seeds for 39 buck, DEAL! lol
You can try Natures green remedies, oregon green seed, rocky mountain seed bank, or great lakes genetics. Nirvana, Herbies, The vault, Gorilla, and most banks advertised here are not US seed banks and are more likely to be seized during delivery. The down side is that most Us banks carry Us breeders and not many of them work with autos.