i come across these coil compressors on ebay, im not sure about quailty of them, ive order some, i thought they were cheap, and might be worth of getting if you dont use them day to day, since there so cheap, ill let you know if there any good.
check them out here if your interested, and by the way im not trying to advertise these, i just thought people might like to know about them
http://cgi.ebay.com.au/ws/eBayISAPI.dll ... K:MEWNX:IT