I started very small, minimal development yet, only sysadmin stuff. Maybe spend 2-3 days on it so far. Setting bitcoin, lightning and shop up.
The cost of running it are small at the moment, a litttle electricity and bandwith but really nothing to think about and maybe 50$ worth in satoshis for domain name and some small things. Also locked up about 500$ worth on lightning, hopefully those will not go up in smoke
Soo could have it running forever in current state. If it would grow i would have to scale up, soo as long as i learn stuff and i think it is fun.