I know of at least one person selling/buying Deco, at what I think is a reasonable price.
Her character name is Marcia, and after I sold her a few Deco deeds, I checked out her shop (sometimes I see colorful runes lying on the ground, which is how I found her shop) where I did notice she was selling some of the things I had just sold to her for, again in my opinion, a fair up charge.
I too, thought as you did, Symphony, about the prices at the Deco Mall. However, I came to the realization that 100 ED's translates into 10mil gold; or 100k gold per 1 ED. As of late, ED's are not hard to find, if you have the coin, tokens, or worth while items for trade, then you can certainly manage the cost of decorating a home.
In closing, this discussion is good, because Domino's is willing to hear you out Symphony. The hardest part to come is accepting that a well thought out idea can end with the answer of no. Just don't give up, try and try again... just make sure its in 20 minute intervals, though.
--Sturger, of Skara Brea; reporter at large, EVO-Herald--