I've seen this excellent shaver rarely go on sale for $99.99 during black friday/similar (the Father's day sales recently were $119.99)--Costco is now selling this item for $109.99 with an additional replacement shaving head included.
It looks like those replacement shaving heads (which you will eventually need) run about $50 on amazon making this deal slick IMHO.
Edit 1: it appears there is some debate about what the included "one replacement shave head" is exactly as there appears to be two parts involved if you wanted to completely replace the head of the shaver in the future:
1. Shaver head foil (which contains integrated blades)
2. Two inner blades
Either way it appears the value of the "one replacement shave head" included in the Costco package is worth $40-50.
Worst case scenario, you can always return with Costco's excellent return policy if the provided replacement shaving head doesn't have the parts you expect...
Edit 2: Panasonic recommends replacing the outer foil system (included for free with this Costco unit) after 1 year and the inner blades (apparently not included with this Costco unit) after 2 years