about wr250x front rotor

hey.
I'm looking for new brake rotor for my wr250x 2010.

I have seen in the service manual that the dimensions need to be: diameter 298mm, thickness 4mm.

-does it have to be a floating disc? the service manual didn't mention that at all, and the costs are very different between the regular and the floating!

-if you can tell me where I can buy it in a good price it will be great! I was looking all over the web :O

-other tips about the rotor very welcome too :)

thanks..