Coffee fell on power button area, liquid damage?

Yesterday, I accidentally fell my little coffee on my MacBook pro button area. I clean up right away. the computer is shut down. Make sure there is no liquid inside. Then, my MacBook still able to use. I did the wrong thing here. I should wait, not using my MacBook after it.

Today, I found that my battery is not working. I have to connect my power source to use my MacBook. When it is connect to power, the light is orange on my power adapter. Battery condition is replace Now. I can use, not harm to my computer.

Today, I went to the apple store for repair. They test my mac. All unit test pass but battery fail. So, they going to replace my MacBook's battery. Since I bought the apple care for my mac. They do not charge me but they say there will be the charge if it is liquid.

So, how much will they charge? Will battery damage because of the coffee? Is it worth to replace the battery? Or is there any cheaper way to fix it?

I bought my MacBook in 2015.