For example, this was ~$100. https://raw.githubusercontent.com/joferkington/scipy2015-3d_... I tried uploading and pricing a "hollow box" version, but it saved less than $5.
However, for this one, using a "hollow box" saved ~30%, (it's a comparable size, but much taller): https://raw.githubusercontent.com/joferkington/scipy2015-3d_...