cheapest wort chiller I know of is a copper coil (any home-improvement store), run a plastic hose to the ends -one hose has a pump submersed in a bucket of icewater (or takes water from the sink faucet) and the other end returns the water to the bucket or sink drain. Viola! cheap and easy immersion chiller. Use a pair of hose clamps on the copper tubing to secure the hoses to it and leaks are no issue at all.