Let's see either on printer paper(doodles which are not worth putting in my sketchbook) and my sketchbook(I have 3). One I just bought which holds doodles mainly, my other one which has some good pictures and some doodles, and my sketchbook which has mainly good pictures but also a few bad which I am going to rip out.
i use 65lb cardstockby Georgian Pacific, i get it at business depot/staples, it's like 13$ CDN a pack, but it's great, and really durable. ink doesn't go thru or bleed like bond paper.