Looking up value for Kris Letang Rookie Card?

I can't remember what deck it came out of but it might have been black diamond. It's an autographed Kris Letang Rookie card with a piece of his jersey on the card as well. I bought it for my brother and just wanted to be able to keep up with what the value of it actually is. I bought it for 100 so that should be the value, i jsut want to know how to look it up without owning the book. Thanks