Generate and print your download cards
For each release, generate as many cards as you want. It's cheap, only 0.10 € per card.
You can even require a valid email address to grow your mailing list.
Then, either export your raw codes in a CSV file and distribute them the way you want or download a printable PDF. You can choose between two industry standard card size (85 mm × 55 mm buisness cards or 38.1 mm × 21.2 mm multi-purpose labels).