For paper I use Hahnemühle protective spray, which I believe is the same as PremierArt Print Shield spray. It is about US$15 a can.
I use three coats, with about 4 minutes between each. I have never tested the claimed UV protection, and pigment ink prints are pretty water resistant by themselves*, but it does add a lot of scratch resistance.
*After seeing a video, perhaps linked from these forums, pushing the water resistance of Timeless and Glamour, I ran an uncoated Canson Rag, Epson 3K VM print under a water tap for 5 minutes, without any noticeable change. The print, after drying, looked no different than before.
Brian A