Put the golden gadget in secret shop. Depending on how many butt-coins it takes to buy the gadget and if you can still get it anymore should determine how much the gold gadget costs in the secret shop.
For example if soul scythe wins it should be 6400-5600 because you can't get it anymore, and if snow ball wins it should cost about 500 (I don't really know what to price a golden snowball) because it's the first thing you get in the snow techweb and it cost 50.