Your idea of a soda can is pretty different from my (and seemingly StonySmith's) idea - your basic can is BIG, and in addition you effectively have three more cans inside it so your are really printing 4 soda cans.
Your model seems well constructed, the problem is the volume of material. The Shapeways price structure in all cases except ceramic relates to volume of material used, and your model has 129 cm3 of material (there is also a handling charge for each model dependant on the material).
Perhaps you are right and 3d printing is not correct for this application - it's a realisation most of us come to at one point or another. But, if you want to proceed you need to get rid of all unnecessary material:
1. If the outer shell is just to enable it to fit in a cupholder, say, what is the minimum structure required to fit/be held snugly?
2. Ditto the internal shapes? I don't know what they are for but is all that structure really necessary?
3. WSF is not water tight in any case - if you want to print in this can you punch some (many) holes (decorative or otherwise) in your model. 3d printing is a way of creating new things but I well understand the temptation/trap of designing for existing manufacturing techniques. These holes can be used imaginatively to both remove volume and make the end result truly interesting/attractive/different etc.
In short I would say you have designed something that fulfils your requirements - now see what you can strip away or re-imagine so that teh end result is better.
Good luck!