Make one. I used two 20 ft coils of coils of 3/8 ID tubing. Made one coil large diameter and the second smaller diameter. I connected the two with a 4 ft piece of vinyl tubing. In the summer one goes in a bucket of cold water and the other in the wort. When the temperature has dropped to about 100f or so I add ice to the bucket. Pretty easy to get below 70 degrees. In the winter when the tap water is cold I put both in the wort.
2 coils of copper $20 each. 4 hose clamps about $.90 ea. Vinyl tubing - about $10. Hose end fitting a couple dollars and faucet adapter a couple of dollars. Approximately $60. About 1/2 to 1 hour to assemble.