CCW rotating. Brand and type of material is up to you. The more rigid will give better performance but usually cost more.
I assume you are a beginner and going to break a bunch of props anyways, may just go with the nylon Gemfan 6X3 CCW ones ( You don't want the ones with a part# that have an R as those are CW rotation). A 4 pack is just a few dollars. I myself like to buy from twistedquads.
Other common brands that are fine are HQ,DAL,APC,Emax up to you.