Assuming you don't merch or whatever.
Also, I doubt this will be of much use seeing as many of us don't play. Probably also out of date. But anyway, huzzah.
1. Craft items
Half earrings with 2nd or 3rd tier potentials sell for at least 20m, from what I remember. Also, farm rare recipes, such as Angelic Blessing Ring; those sell for a lot. If the ring is unequipped, those sell for a lot too (cause, you know, if they're equipped you can't sell them). So yeah, craft until you get decent potentials and sell your products.
2. New Leaf City Deputy Star repeatable quests
The rewards for these quests are high if you're extremely low on mesos. If you can't defeat Bigfoot or HH on your own, ask a stronger friend to come along.
3. Loot drops
If you're at a higher level, say 130+, train in areas with monsters around your level, and loot all of the drops. Sell the etc drops to NPCs, unless you know people who buy them for more. Although 100 mesos seems small, after you loot 1000 or so of the etc drop, you'll have like 100000. Too lazy to check the math on that. Also, the equip drops can sell 40k+ to NPCs, and some people would buy them for more.
Pieces of Time, which drop from Temple of Time monsters, sell for around 1m in the Free Market.
4. I forgot, but feel free to add anything in the comments.
Also, I doubt this will be of much use seeing as many of us don't play. Probably also out of date. But anyway, huzzah.
1. Craft items
Half earrings with 2nd or 3rd tier potentials sell for at least 20m, from what I remember. Also, farm rare recipes, such as Angelic Blessing Ring; those sell for a lot. If the ring is unequipped, those sell for a lot too (cause, you know, if they're equipped you can't sell them). So yeah, craft until you get decent potentials and sell your products.
2. New Leaf City Deputy Star repeatable quests
The rewards for these quests are high if you're extremely low on mesos. If you can't defeat Bigfoot or HH on your own, ask a stronger friend to come along.
3. Loot drops
If you're at a higher level, say 130+, train in areas with monsters around your level, and loot all of the drops. Sell the etc drops to NPCs, unless you know people who buy them for more. Although 100 mesos seems small, after you loot 1000 or so of the etc drop, you'll have like 100000. Too lazy to check the math on that. Also, the equip drops can sell 40k+ to NPCs, and some people would buy them for more.
Pieces of Time, which drop from Temple of Time monsters, sell for around 1m in the Free Market.
4. I forgot, but feel free to add anything in the comments.