http://www.gamersgate.com/DDB-T3APBP/tropico-3-gold-edition-bundle
Unfortunately it can't be activated on Steam, but $2.50 for Tropico 3 and the expansion is a steal at this price. Not sure if it's a pricing error or not, but it is what it is.
Pretty good deal on a brand new game. Online only, here are the links:
X360: http://www.walmart.com/catalog/product.do?product_id=12177188
PS3: http://www.walmart.com/catalog/product.do?product_id=12177190