Does anyone know a website that tells u the value of trading cards?

i collect pokemon and yougioh cards and i was wondering how much they are worth

Does anyone know a website that tells u the value of trading cards?
i dont know but i try my best to ask people that same question and even now i work alone so i go to google,com and type what i need to find
Reply:No, but I know someone who has "THE Base Ball Encyclopedia" Book, copyrighted 1969, third addition. Worth lots of $$$$$, and I think he wants to sell, interested ? oh, it has 2,142 pages !
Reply:I wish, but it in stores sadly, their not going to waste printing it in a magazine and then you find it on the net.