請幫我改這兩句英文

1.如果我在吃自助餐途中,想問待應有沒有飲品附送,這句對不對?
do i have any drink accessory to the buffet?
Does the drink included to the buffet?
2.如果我想問,這杯可樂要不要付錢,這句對不對?
is the Coca-Cola free?
Perfectly okay.

you can say 1. Does my meal come with a drink?
well, your translation sounds very awkward because you used the wrong word,

an accessory is a subordinate or supplementary part, object, or the like, used mainly for convenience, attractiveness, safety, etc.,

you use it in a sentence like this "The accessory on the dress makes it look very elegant"

and you are right on the second one, if you want to make it more clear, you could even say "The coca cola is free right?"