These are large, round stickers. They're probably about 3 or more inches in diameter each, so they'd be a suitable item for binder decorations...or something equally big. Each one is all in blue & black, with 'jumping punch' Sonic X art. It says "SuperSonic Speed" along the edge. There were also black shirts made with this same design, in this color as well.
These are from Hot Topic --but probably in 2010 or 2011 or so. They were costly, something like 3.99 or 4.99 for just 1 sticker.