I personally use a 5 gallon bucket (free at some places, $5 at Home Depot). Just make sure you get a lid for it. Then while you are at the garden center, pick up a planters dish (the dish that goes under a planters pot) that is big enough for the bucket to fit in with an 1" or so over hanging.
I placed the lid on the bucket, then I drill two 3/8" holes at the bottom of the bucket about an 1/2" up on the side, Then in the bottom of the bucket, I cut a 6" hole right in the center. This will be the hole that you fill the bucket.
Place you a concrete block where you are going to have their waterer, sit the planter dish on top of the block (making sure that it's level), fill up the bucket with water through the 6" hole until it's full, Then when you are ready, turn the bucket right side up and place it in the center of the planters dish.
I have been using this design for about 6 months and it works great. Now that my flock has grown, I will be adding another. Since my buckets where free, it only cost me $5.
Good luck