I realize it's not a 2D product, but Gamr7 is having a special promotion on it's Urban Pad City Creator, for 3D. (Although you could export as 3D into a renderer to create a background for your 2D work).
Anyways, the promo is if enough people order it before October 3rd, it'll only cost $29. It's a $700 software package initially. If they don't meet their quota, they'll refund the $29.
For $29 it couldn't hurt to take a look: http://www.gamr7.com/init/default/index
Urban Pad City Creator Promo
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