I would say if smth has already been posted (I think currently you are notified that it is already posted but it still costs 1 sat, correct me if I am wrong), increasing this to be 1000 sats would solve it.

Another idea I can think of is the time limit to be increased. Currently if I post a link it costs be 1 sat and 10 sats for the next 10 mins IIRC. Maybe you can increase it to be 50, but the time can be increased as well to lets say 30 mins or 1 hour, why not.