I need a simple fix on a model

So I have a model which I made hollow as to save on the cost of printing, but it still gives me the price of it being solid.
I assume it's because of the model having clipping within itself, so I was wondering if someone could take a look and make it contiguous - put the sides together so that there isn't clipping.
Attached is the non-hollow version -- if someone could hollow it out too, that'd be cool, but I think I can manage that part myself.

When you make a model hollow you have to create a 'hole' that goes from the outside to the inside. If you don't Shapeways will just ignore all of the internal faces and treat it as a solid. Your model needed to be repaired. Open it in http://www.netfabb.com/basic.php and click on the first aid icon. click on 'automatic repair' and 'apply repair' then export part as STL.

Now beware, if you just delete a face on the outer surface you will wind up with a non manifold object, unprintable. Its similar to drilling a hole in a coconut to get to the milk, a tunnel through the shell. Be careful about the directions face normals point. They need to point inward on the hollowed out areas surface, outward on the outer surface. When you connect both surfaces, they will all be pointing in the correct direction. This is called a well defined surface.

It was a nice model, by the way. Most of the problems are fairly obvious, but few in amount, mainly concerning the sections regarded as shells(6). Normals were perfect, 1 interior edge was the oddity. 4 holes, the odd edge, and 6 shells the problems. Fix these, hollowing it out will be a breeze.
Keith