Check out their website; the FAQ page tells you what you need to know, confirming what IrishLake said about first year expenses being higher.
http://www.wku.edu/wkugreeks/panrecruitmentfaq.php
My mother-in-law graduated from WKU and was in a sorority, only in her day they were locals that were later absorbed by NPC sororities. I now have a former co-worker whose oldest daughter is involved in WKU Greek Life and really loves it!