A simple step by step guide by @chriselsasser.
** Before starting you can check your local rain-water collection regulations at http://www.enlight-inc.com/blog/?p=1036
All of the items you will need for the project. I’ll always recommend supporting your local hardware store, I bought what I could for supplies locally but did go to Home Depot for the 2 most important pieces here (the Rubbermade ‘Roughneck’ 10 Gallon bin & the Bulkhead Union Washer). This entire setup can be completed for approximately $30-35 depending on what supplies you may already have.
*Bulkhead Union washer (this one is made by WATTS item no. HPL-1871) = $12
*Threaded PVC male end with plug stop = $4 (found in the same plumbing aisle as the Bulkhead Union washer
*Plumbers tape = $1.50
*RubberMade roughneck bin w/top = $8 (10gallon, they also have an 18 gallon option, located in the gardening section)
*Window Screen/Mesh ~ $6 (any fine mesh will do, this is to keep bugs and debris out)
*Gorilla tape / Duct tape ~$5, to secure the screen to the underside
*1 3/4" hole saw bit. You’ll need a drill, ½” drill bit and a 1 ¼” circular drill bit (if you choose this exact Bulkhead Union). NOTE: there are kits on amazon that come with the parts necessary for a rain bin, many of them are threaded to a size unique to that company - meaning you then need to order a whole new drill bit size which is not available in most stores. The items I’m using are in standard sized threading / bit sizes.