To buy a ship, you must be able to finance it.
How do I finance a ship?
Unfortunately, the Storekeeper's note of credit severely limits your selection of ships.
You can only buy the cheap ship at the far end of the dock near the rear of the screen.
Ask Stan about the cheap ship, and offer him the note of credit to finance it.
Now, you need to bargain in order to talk Stan below the 5,000 pieces of eight credit you have.
Bargaining for a ship is a lot like bargaining for a used car.
To find out Stan's price at any given time, ask "Well, what do you think its worth?"
To lower his price, do what you'd do at a used car lot.
Turn down the extras.
Threaten to walk out.
Make a low offer.
Once you've lowered the price below 5,000 pieces of eight, you can buy the ship.
Stan will meet you at the dock in town after you obtain a three person crew (not including yourself).
How do I get a crew?