There are a few different ways to go about making stopper but this is the quickest and easier DIY way I have found.
Cut a few pieces of wood about 2" long. I used a paint stir stick because that is all I could find at the moment.
Drill a whole into them about 1/3 of the way down (or up:)) This is for the screw
I moved it up as high as it could go once inside. This will stop the drawer form coming out but you can reach in and move it down in case you need to take the drawer out all the way.