Step 1: Gather your materials.
2 2.5 Gallon Buckets
3 1.0 Gallon Buckets
2 approximately 1 inch by 1/4 inch bolts
2 corresponding nuts, washers
1 Hose Washer
2 Hole Saws (I used a 2" and a 1")
1 Utility knife
For the buckets I always raid my local bakery. With a little effort on your part they will usually set them aside for you. Just be polite and ask. (They are, by the way, great buckets for lots of other uses and projects as well.)
There might be some other incidentals things as well.