Last time I was on the Glory (09/06) - I received a facial and massage for roughly $70.00. My husband had the warm stone massage for about $70.00 also(he is a convert and plans to have one every day on our next cruise in September).
If you wait for port days - services are much cheaper. Also, services go on sale toward the end of the cruise, but when they do, they book up fast.
Hope this helps.