Depending on the material they're made of, you could paint them, stencil them, cover them with contact paper, wrap them in fabric or twine. I guess it depends on your style as well.
You can wrap them in rope or cover them with fabric, using spray adhesive.
The same way you would if you were gluing curtains to them, except: you make your own curtains, and rather than Stitch forever: Please use Glue instead.
They make spray paint for plastic ( krylon brand? ) E Z. Must do outdoors on newspaper or tarp or old sheet.
Sewing removable slip covers is another idea for 'disguising' storage bins.