what i did to get 7 million in less than an hour, was go to a friends town, and nook was buying for 600 something.
and i time traveled to sunday and bought turnips, went there and sold, left, bought more turnips, went and sold.
and so on
like i said i got 7 million.. in about 30-40 minutes?
Time traveling is an extreme. There's also another drastic measure.... hacking. Duplicating the royal crown...
Here's a major extreme...
Cut down all the trees but coconut trees near the beach. There are about 25 bugs scattered across the entire town. Doing this drastic method will insure that during summer after 7pm the rare expensive bugs are on all the coconut trees. These bugs are all 6,000 bells or more each. It is easy to get 100,000 bells for each full load of rare bugs.