- Run a contest to uncover hidden seed phrase for a wallet 
- Something sharable, that's how hotmail & youtube did it back in the day. Every shared email or link was its own advertisement
- Provide a new service that people actually want/need 

hodlpleb

I want to get people to sign up for the beta testing so they can see how good it is. 

in_bits

you are right here - SN, and make it so good that stackers would talk and share your good stuff.

Natalia

Have a product that's good and useful and doesn't abuse its userbase and Bitcoiners will just shill it to each other.

nerd2ninja

boost your post on stacker news.

for 100k sats you can probably get 12-24 hours of screen time in front of thousands of bitcoiners.

i doubt there are any more cost-effective strategies today.

Ask the organizers of the Bitcoin Conference if you can run a fleet of drones above the venue where the drones form a QR code? Lol.