I bought the Simplicity Side WInder at Walmart for about $20 about a year ago. It turned out the Cheapo Brother I bought still in it's box at the thrift store for $20 had a broken bobbin winder!
It's ok but it is not a quality bobbin. I've tried different surfaces, I've tried battery and direct power. It consistently overfills the top half of the bobbin and goes down in a V shape, I add in an extra loop to the process with my finger and try and keep the fill even.
It is not a tight fill either, and some machines can be finicky about that. But basically I only get half a bobbin compared to winding one on my other machines -- unfortunately this bobbin doesn't fit any of my other winders.