Necklace part costs more than I thought

I've made a part for a necklace, but I was suprised when I saw the price for it.
I was wondering if someone could look at it and fix problems and other things that could bring the price up.
It is a square with tiny squares sticking out of it.
It was made in SketchUp 8.
Thanks

Can you export it in *.stl format?

Here you go

Not sure which material you want to use but part of inner wall can be scaled out (make thinner wall)

try this (Attachment) (check units before uploading)

Are the walls too thin to be made out of stainless steel?

yes they are too thin
Min: 3mm. You have cca 2mm