STEP ONE. Ask at your local grocery deli for empty frosting buckets - the largest they have (We were able to score them at Costco, Food Lion and Lowe's Food). Cut a 3-4 inch hole in the top.
STEP TWO. Buy or scrounge some 3 inch diameter PVC, drill holes all around and cut into 2-3 inch sections. Use one to measure up from the bottom of the bucket and drill a large hole in the bucket at the top of the PVC support.
STEP THREE. Try your local dollar store for plastic colanders. Cut the handles off, then cut out the bottom solid circle and drill two holes, one on each side of the central hole. Attach the PVC support to the colander using the holes drilled in each.
STEP FOUR. Place the colander in the bucket, resting on the PVC support. If you are concerned about soil falling through the holes (some do, some don't), you can use screening material or landscape fabric to hold the soil. Fill the hole in the colander first then continue up the bucket with soil, moistening as you go (use a good organic potting soil mixed with some compost or mix your own from compost, potting soil, peat, soil conditioner.
STEP FIVE. Fill the bucket all the way to the top with moist potting mix. Firm gently. Make a trench around the edge and fill with 1/4 cup or so of a good organic balanced fertilizer (I used Garden Tone). Plant your plant (here a squash) in the middle of the bucket, watering in well. Cut a 3-4 inch diameter hole in the top of the bucket and place the top carefully over the plant. Fill the bottom reservoir with water and voila! A self-watering container for about $1.25 plus the soil!