Cheap blank led window key caps???

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I would need blank keycaps with led window like these http://cdn6.bigcommerce.com/s-ktpi93fl/products/145/images/476/DSA_Dolch_2__83031.1435349554.1280.1280.jpg?c=2 some 20 pieces or more. And they should be cheaper than those (8USD for 4 pieces at pimpmykeyboard). Has anyone got any idea where to get these? And they should fit on these http://www.ebay.com/itm/12-PACK-CHERRY-MX-Red-Mechanical-Keyboard-Switches-Microswitch-Keyswitches-/111964419797?hash=item1a119976d5:g:Lp0AAOSwQItT~d9Z . I'm new to keycaps and all this. So all in all, i'm trying to make a custom shape device with led window keycaps. Thanks to you all