You can buy one from eBay at http://business.shop.ebay.com/Ice-Machines-/67171/i.html?_nkw=used+ice+machine or a refurbished one at http://www.icemachineclearance.com/product-list.php?cid=1. You can buy a second-hand one at http://www.bid-on-equipment.com/6210.htm.
Target offers ice machines but they are all new ones. Used ice machines are available from ebay, http://www.icemachineclearance.com/product-list.php?cid=1, and www.nextag.com.
Hoshizaki ice machines are used to make ice. Actually, they are industrial size ice makers so you typically wouldn't find them at a home but more at restaurant and other business establishments.
Portable ice machines are fairly readily available from retailers like Walmart and Bed Bath and Beyond. They are also available online form retailers like Amazon.
since you are Looking for ice making machines i would suggest looking in your local yellow pages for local places to buy them or going onto craigslist to widen your search
Ice Cream Machines.
I am sure if the Manitowoc ice machines don't work very well once you buy it, you can return it for a refund. I would look up reviews on them on the computer before buying.
Cornelius ice machines are large high-capacity ice makers generally used in restaurants and hotels and other uses for which a high volume of fresh ice is required. You can visit the Cornelius web site for more information at http://www.cornelius.com/
Ice cream machines are not advertised since the cost of ice cream has been driven low by competing companies. Moreover, the consistency of ice cream created by such machines is not very firm.However, you can quite easily buy one from macys or amazon.
There are many sites online, including usedvending.com and vendweb.com, that sell used venidng machines.
There is actually a smaller ice machine that can be put in a freezer. This is a great way to make large amounts of ice without having to buy a special machine.
I think dry ice is solid CO2. How it works I'm not sure.
Ice machines typically produce about 70 killograms of per hour.