I have more then 100 yu-gi-oh and pokemon cards where can i sell them?

You can determine the rarity of your Yu-Gi-Oh cards by looking at the color of the text found at the top of the card. The most common Yu-Gi-Oh card title color is plain black which is a common rarity, then the more rare cards have a silver title color which is secret rarity, and finally the rarest of all the Yu-Gi-Oh cards will have a gold colored title which is usually Ultimate rarity. (Also rare and special versions of the god cards will have a title color of "divided" silver, which is similar to the silver title text but has certain patches of the text shinier than others.) Second, I think that selling your cards on ebay would probably be your best shot at getting a reasonable price for your cards.