What's the fastest way to farm gold?

Use this tutorial.

In text form,

• Make a new ruleset that's based on stocks

• Set stocks to 1

• Set time limit to 1 minute

• Set CPU level to 1

• Turn off stage hazards

• Turn off items

• Set launch rate (under advanced options) to 0.5%

• Save ruleset

• Choose any character, leave CPU at random

• Choose any stage

• Move to the middle of the stage and repeatedly duck (Coin rewards appear to be partly based on how many inputs are fired)

• The CPU will likely be unable to kill you

• After 1 minute, kill the CPU in sudden death (or be killed, it doesn't matter)

This should net you 300-500 coins. Commenters say they reach 1k with 2 players ducking, but I can't replicate this.

Addendum: To save more time, set stage selection to random and turn off all but one stage from the list of available stages that appear when selecting random.

I managed to get 55k gold after a party with a bunch of people playing Smash all night, but that dried out pretty quick... The 1-minute test game as mentioned above just netted me 338g on first game, then I did two player, and netted 459g with same ruleset.

It's very grindy, but without a party lasting hours, it may work. I forget how much you can get with online games... but at that rate of 1.5 mins per game (counting load times) and 300g per game, that's 200g/min, 12,000 per hour, which means 1h15m of total grinding per legendary bought minion.

It appears that Spirits points shop sells different spirits than the gold shop, so I guess we'll need a ton of gold to get all the spirits!