You will need:
Mason jar (best to get a tall one, these were a little too short)
Sewing kit (or collection of sewing things, needles, pins, safety pins, tape measure, small scissors, thread)
Fabric (I used quilt squares, but it would be cheaper to use scraps)
Batting or cotton balls (for the pin cushion)
Cardboard (I used a shoe box lid)
Hot glue gun and glue
To make the pin cushion:
Trace the jar lid onto the cardboard (not the screw top but the round silver part that covers the jar) and cut it out.
Hot glue some batting or cotton balls to the cardboard, as much as you want.
Glue the cardboard (with the batting on top) to the jar lid.
Cover it with fabric, and hot glue around the bottom of the lid to secure it. You will burn your fingers.
Then fill the jar, put on the lid and the screw top thing, and put some pins on top.