Board Thread:Questions and Answers/@comment-12913802-20161106203703/@comment-27701762-20161106204517

I think it might still be possible if you do the various selling tricks (i.e. go to Tem Village and sell any items, purchase and sell Cloudy Glasses from Gerson, etc.). There is also a character in Waterfall that ferries you from one side to another of one of the Undyne arenas and pays you 3G each time. Then there's the Ball Game in Snowdin, which has a payout of 1-3G depending on how you play.

But there are no more fights, so you can't earn Gold that way.