This is the 345th most frequent Icelandic word.
kosti
The Icelandic word "kosti" means "advantages" or "benefits" in English.
Here 'kostum' refers to advantages or benefits, related to choosing among alternatives.
Ég geri grein fyrir kostum þessa valkosts.
I recognize the advantages of this option.
In this context, 'kosta' refers to options or choices, pertinent to decision making.
Hún verður að velja milli tveggja kosta sem báðir eru spennandi.
She has to choose between two options, both of which are exciting.
Used here, 'kosti' refers to features or attributes inherent to something.