I decided to brew 2 extract batches at a time to save setup and cleanup time, so I figured I'd need a chiller. After searching/reading what others here have made, I decided on 50' of 3/8" pipe and made it with 2 coils. I got the pipe at Menards for about $40.
The inner coil is wrapped from the top down, and the outer back up. I first wrapped the inner coil around a small water jug. Then I wrapped a couple towels around the coils to increase the size, and wrapped the outer coil back up around the towels. Hose connection is 3/8" compression to 1/2" female pipe, then 1/2" male pipe to male garden hose. The exit end has no hose connection.
It cooled 2.5 gal of extract to 80 deg in less than 10 minutes. Yes, thats snow on the ground, so the water was about 60 deg.
The chiller works great, and made wort chilling so much easier.