Sometimes you see a resource, and you say "Now that could prove useful!" An example is something seen at a math conference.
Clear Educational Solutions offers InstaGraphs, which are self-adhesive grid and graph pads. Basically, they are non-yellow sticky pads with graphs on them, allowing anyone to quickly make a "more" accurate graph.
InstaGraphs are available in fourteen different styles for different needs, such as representing fraction computations, graphing trigonometric functions, graphing polar functions, representing unit circle ideas, and exploring patterns on the 100-chart.
As to cost, an InstaGraph pad includes 50 self-adhesive sheets, for the amount of 66 cents...when 20+ pads are ordered.
Quite reasonable, given my own trouble of trying to draw a graph on my hand-drawn coordinate system! I know you can get the same graph dynamically on a calculator, but such is not always handy...or possible to return to a student on their homework.
Note: In case you are concerned, I am recommending Instagraphs without being asked...and pro bono!