How to line the bottom of a planter on the cheap

Say you are filling your planter box or flower pot with dirt on the deck or inside the house and you do not want dirt coming out from the drainage holes, but you still need the planter to drain.  You can run to home depot and get some landscaping cloth (about $10).  But why do that?  Just line the bottom of your planter with newspaper or brown paper grocery bags.  The paper will allow the water to drain while keeping the dirt from falling out.  Also the paper will retain moisture, so less frequent watering needed.

I would stay away from using magazines, as all that paint on magazine pages will most likely prevent water from draining.