Sweet Onion Creations (whom we've covered before) has posted several very useful tips for reducing the costs of printing 3D models. The article focuses on the Architectural crowd, but the tips are useful for anyone printing 3D objects. Some tips we noticed:

• "... think about doing a hybrid model - This entails a complete model with the site and the building done at a small scale and smaller sectional models are built individually at a larger scale to show specific features of interest."
  
• "... saved tremendously on their modeling costs by hollowing out the model ..."