I think having none at all would look better than that thing. Or if you dont have the money now, just dont put anything in, but watch ebay for a good deal on a used one.
It's not always "about the money". Having a real coin-door and not actually putting quarters in it to ring up credits is about as useful as a decal, and more work to install. And while that act is admittedly fun for the first handful of quarters or so, recycling them can get a bit tedious, and the "coin up button combo" eventually wins out. That was my experience anyway.
It should also be mentioned that there's a separate version designed to be used with our NovaGem CDR buttons for both looks and function. Both style of decals are, if fact, pretty popular items, with most folks being quite pleased with them. Of course, their opinions may differ because they actually own one

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RandyT