There's no one better to ask about this than Stan himself.
But he says you don't have enough money to buy a ship.
Maybe you could get it on credit.
When you ask about credit, Stan says that he can't offer it but the storekeeper might.
Pay the storekeeper a visit. (If he's not in the store, ring the bell.)
Now, how can you go about getting credit from the storekeeper?
Talk to him, and tell him you need some credit. (In order to ask for credit, you must have already talked to Stan about it.)
To get credit, you need a job...
Or you need to tell him you have a job.
He'll open the safe and remove a note of credit.
It would be nice if you too could open the safe.
Why don't you memorize the combination?
Whatever job you tell him you have, he won't believe you.
Apparently, you can't get the note of credit honestly.
You need to purloin the paper from the safe.
But to do this, you need to get rid of him.
How did you do this before?
Ask him to go to the Sword Master's again.
When he's gone, open the safe, and take the note of credit. (If you've forgotten the combination, leave the store, and come back in. Then talk to him about credit again.)
Bring the note of credit to Stan, and you can bargain your way to a ship.