You don't have to pay extra for breakfast.

你不必付额外的早餐钱。

youdao

If your luggage is overweight, you'll have to pay extra.

假如你的行李过重了，你得付额外的运费。

《新英汉大辞典》

For example, you may have to pay for any food or drinks you have on the plane, and you may have to pay extra if you check baggage instead of carrying it on the plane.

例如，你可能需要为飞机上的任何食物或饮料付钱；如果你选择托运行李而不是带其上飞机，你可能需要额外付钱。

youdao

Every time the farmers buy seeds, fertilizer or other inputs, they pay an extra five percent in addition to the price.

VOA: special.2010.05.11

but you sort of pay extra to be here, where all the people is, and

但是你像是支付了额外的费用来这里，所有人也都是如此，

卡姆登市场的魅力 - SpeakingMax英语口语达人

This means that you would have to pay extra money at the end, but they decided that people have trouble doing that.

这表示你在最后必须支付额外的款项,但他们觉得人们对偿还额外款项会有困难

耶鲁公开课 - 金融市场课程节选

Precious metals traders need to pay extra close attention to the U.S. grain futures markets today.

FORBES: Comex Gold Up On Short Covering, Bargain Hunting, Bullish Outside Markets

Ms Jones-Napier says her customers are also happy to pay extra to support the company's values.

BBC: US firms put social values before big profits

And householders generally grumble a lot if they have to pay extra to have their rubbish collected.

ECONOMIST: Less is more