It is pretty cheap to build your own. I built one out of a 3/8in 50ft coil. The coil at the Lowes by me is $45. For hardware you only need some vinyl tubing from there in bulk at $3, a couple stainless hose clamps ($0.92 per pack), and a $6 hose adapter. If you want to make it a tad stronger grab 6 ft of UN-insulated heavy gauge copper wire from the bulk wiring area for a few bucks and weave it between the coils. For $5 more you can use 1/2 inch tubing. It takes 5-15 minutes to make and you cannot purchase a 50ft chiller for less. With my ultra cold well water in cold weather I can chill a 5.5 gallon batch to 70 degrees from boil in as little as 7 minutes.