UV-A penetrates much deeper into the skin than UV-B and is useful in keeping skin firm and without wrinkles by degrading elastins and collagen.
Facial creams that claim UV protection prevents damage only against UV-B rays. At this time, companies are not required to back up UV-A claims on their labels.
UV-A penetrates windows so even if work work indoors, you still need to be protected from UV-A rays.
More expensive creams do not give better protection. Ask your dermatologist for specific recommendations.