I have been using mspaint to make figures, which proves tedious and leads to scruffy results. I need to make a couple very simple vector diagrams and simple graphs. Something that would easily allow me to re-create the attached file would be perfect.

 

Until somebody comes up with a better solution you could try the advanced version of Paint.

 

http://www.getpaint.net/download.html

http://pubmate.tk/s/index.php

Vector graphics is a good idea, like SVG files, there is a free program called Inkscape that makes vector graphics. There is also LaTeX which is another type of image generator and it has more addons. There is a bundle+installer for windows called MikTex and there is another called TexLive which I think is more popular (I've only used on Linux). LaTex was cool because it let you draw and image using code, you can just write something like this:

 

line(point(13,43),point(23,42)) and it would draw a line connecting two points (not a real example). I think LaTex is your best bet.

My two recommendations would be:

 

Inkscape

Draw.io

If you only need for your personal use (coarse drawings) then you can also use Math-o-mir. I made this in about 10 minutes.

Edited July 3, 201510 yr by Danijel Gorupec

I haven't used it (and I don't know if it would be appropriate for this) but this looks quite good: http://pencil.evolus.vn/

If you only need for your personal use (coarse drawings) then you can also use Math-o-mir. I made this in about 10 minutes.

mom_handdraw.png

 

Or Octave: http://www.gnu.org/software/octave/(but it might be overkill)

Or iPython: http://ipython.org/