Send Nintendo Switch game by post?

I sold a Nintendo Switch game on Ebay classified ads now I have to send the game to the buyer. Fortunately, it's so small that I could send it by letter. Unfortunately, I don't know what to pay for it, so which stamp, so to speak. Does anyone know that maybe?

80 cents at less than 20 grams

95 cents at less than 50 grams

155 cents at less than 500 grams

If a Nitendo game doesn't weigh much, 80 cents is enough

If the game is in a case it will cost 1.55 euro. Only the module could still work as an 80 cents letter