While MS Paint isn't the most fancy program to use, it's still a good one. Here's how I used to do my renders back when I used MS Paint:
1. Copy the image you wish to render and paste it into MS Paint.

2. Select the "Polygon Tool" and then click "Fill". Make sure the settings in "Fill" are set to "Solid Color". Also make sure that your primary color is black and your secondary color is white.
3. Trace the lines with the "Polygon Tool". Remember to connect the ends of each line, so that the selected region will become filled with white. It's best to do this in chunks, because it makes it much easier and you can go back and erase unwanted lines later.

4. Erase any unwanted lines.

5. Colour it however you wish.
