Numista is not the place for selling or buying numismatics. https://en.numista.com/help/can-i-buy-or-sell-on-numista-7.html
100 dollar set was sold on ebay for 600 USD. You can try selling there or go to local numismatic stores. If central bank still accepts them as legal tender, nominal value should be around 333 USD. No idea how much they are worth as gold foil. If specifications on apmex were for whole set, then gold is worth only around 100 USD