Dummies that are intended for cakes have a tight smooth contstruction that allows them to be washed and re-used. Regular styrofoam will work, but it can't be easily cleaned and re-used, unless you cover it first with contact paper or something similar.
You can find reasonable prices at several places including
dallas-foam.com
Thank you for your response!
I think my original post might've been a bit confusing though, so I'll give examples of what I mean.
Here's the first:
http://cgi.ebay.com/Round-Foam-Cake-Dummies-Dummy-Cakes-Fake-Cakes_W0QQitemZ110080848373QQihZ001QQcategoryZ3268QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
And the second:
http://cgi.ebay.com/12-x-4-Round-Cake-Dummy_W0QQitemZ160070694863QQihZ006QQcategoryZ46281QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
I guess what I'm confused about is.... well, the difference between the two. Why can I get an entire 5 tier cake dummy for the same price as one layer? Are they different materials at all, or is one better quality than the other? They both look good, so I'm a big confused.
Thanks in advance!
All you're seeing is two sellers who charge vastly different prices for the same thing. My guess is that one is the manufacturer and the other is a retailer. They're the same material.
I've got "pebble foam" dummies--like the ones above, and floral foam dummies (you can't really buy those--I got them from classes at the Wilton school and they don't sell them and the supplier won't sell them except in huge quantities). I prefer the floral foam dummies because they are sooooo easy to smooth, contour, and carve. If I need to make a dummy--like a small square or round, I'll use my Michael's coupon to get a piece of floral foam and cut it/glue it myself. It works just fine.
The pebble foam dummies are cheap and sturdy, so just get the best deal you can.
Rae
All you're seeing is two sellers who charge vastly different prices for the same thing. My guess is that one is the manufacturer and the other is a retailer. They're the same material.
Sweet! I'm not worried about getting something super durable or fantastic right now, I really just need something that'll work. Ya know what I mean? That's awesome though, now I know who to go through. Thanks! 
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