Whitelines graph paper
Some of you may have heard of Whitelines, a kind of graph paper with white lines on a light gray background. It’s great; your nice axes (the plural of axis) don’t get obscured by heavy lines. It’s also kinda expensive, $9.50 for 160 spiral-bound pages. That’s about six cents per page. Well, you can print your own, here (it’s called “inverted graph paper”), for about four cents per page (about three cents of ink per page, and about a cent of paper per page). I like line thickness at 0.5 and color at #DEDEDE.