Where certain art supplies can be found? Cheap?

Im very artistic and creative and i wanted to expand my collection of crayons and markers and such. (coloring/drawing utensils) does anyone have any idea where i can get oil pastel crayons cheap? And i also wanted these crayons that are more waxy than regular ones and come in vibrant colors. I dont know what they're called but thet look really cool on black paper. Please help. Thanks! :)