How to pay for a single ticket to the driver of the public bus in Lübeck/Travemünde, Germany?

Getting off Finnlines ferry to Travemünde at ~7am and need to reach Lübeck Hbf (main rail station). Finnlines web page specifies, that buses 30/40 and 31 can be used for that either directly, or via Lübeck-Travemünde Skandinavienkai bhf.

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Lübeck public transportation page in English says that single travel tickets can be purchased from a bus driver. The amount is EUR3.20 per person either way.

What forms of payment does the bus driver in Lübeck accept? Should I have exact change, credit card, or have some rechargeable card? If the latter, how do I get one before arriving on German soil?

Is the ticket sold on bus valid to continue journey on a DB train (Lübeck-Travemünde Skandinavienkai bhf -> Lübeck hbhf)?

Solution When using Finnlines ferry without a vehicle, you will be transported to/from Finnlines terminal from/to a ferry by a shuttle bus. If you kindly ask the shuttle driver to drop you off at the Lübeck-Travemünde Skandinavienkai bhf, they will comply (and open a special staff-only gate that leads from the harbor to the pedestrian underpass below the rail bed). You can buy rail tickets at the ticket machine on the station platform. US issued credit card was accepted by the ticket machine to the right (facing away from the rails). Hope, that helps.