IMO, 1 free post would be nice. (I don't know if "Login with Lightning" requires a full node. If it also works with lite wallets such as Blue Wallet, you could require it to get the 1 free post credit. Spammers probably won't spend time to create a new wallet for every link.)

x sats may be a symbolic amount (less than $0.01), but depending on circumstances, it may be difficult for people to acquire their first sats, so a free post (and the opportunity to earn some tips from it) could help to onboard people to Bitcoin and Stacker News, without barriers.

(In some places, it may be easy to buy a $10 Amazon gift card from a local store and sell it on Robosats, or use an Azteco vendor or KYC-free Bitcoin ATM, but many countries don't have these options and it can be difficult to find a local cash by mail/cash in person seller for low amounts.)