I am handy but no miracle worker. I am in Finance by day to give you a sense. I found the most economical way to obtain one was to BUILD IT!
Go to Home Depot or Local Plumbing Supply for the appropriate Copper Refrigerator tubing....I think I used 3/8. There are "How Tos" all over the internet. I got a spring tubing bender to prevent kinks and then got hold of a long round object of the appropriate diameter (A few inches from the walls of the pot). Then Wrap!
Second set of hands is helpful and I used a paint can for my template.
To get water in/out I used clear tubing from Home Depot with an ID to match the OD of the copper tubing. I used worm clamps to lock it down and prevent leaks and bought a barbed hose attachment for the water supply end.
All in it was probably less than 2 hours of work and way cheaper than buying one at a LHBS.