Go to the fridge and farm the crystalisk, it's pretty good for money.
gaming.stackexchange.com/users/33521/RIGECK
Really good way to farm money is during the Mission to save Roland.
Just complete that mission over several times and you can build up a fortune of around 100,000+.
Another good way to farm is to use the Slot Machines in Sanctuary, but the trick to it is, make sure you have a full party.
For each time you win money on the slot machine, everyone else in your party does as well.
Just cycle out between 2 people and keep gambling and selling any weapon that you aren't interested in.
My party made around 50,000 in about 2 hours, not too mention, we got some pretty fantastic weapons.
gaming.stackexchange.com/users/33252/likezoinksSCOOOOOB
Run through thousand cuts, ignoring all mobs en route, to bunker.
Bunker is an unpopulated zone home only to the boss BUNK3R, who is easy to beat using a corrosive sniper.
On normal he and his loot-splosion are lvl 26 and he yields 10k xp, erridium, $$, and all rarity of items including a legendary shield.
There is a save point and a vending machine in Bunker before encountering BUNK3R so merely sell all the stuff you don't want to use for around 20-30k per run and continuously save/exit/resume games to farm the boss to your heart's content.
If you're good (or a sniper specced assassin)
you can down him in 3-4 minutes per run from the coveted area up top..
I spent more time looting him than fighting him since I look over each item and he drops around 30 things on average.
gaming.stackexchange.com/users/33532/Shoot n loot
The easiest way to get the final challenge level of For the Horde!
is to farm bosses (kill them, get lots of guns, sell guns, repeat) at a high level.
Unless you farm it earlier, you probably won't have the challenge by the end of playthrough 2 (I sure didn't, but never farmed).
I recommend waiting and doing this during playthrough 2.5 unless you think you'll quit before then.
You'll easily get a few hundred thousand per run this way and can max the challenge in under an hour.
The easiest way to farm bosses is to get yourself a The Bee shield; Hunter Hellquist drops them; he respawns after the mission
This Just In is completed after the end of the game.
Kill him, quit, restart, kill him again until he drops it.
The shield gives overpowered amp damage.
Use The Bee and pretty much any Shotgun and you can easily slaughter Terramourphous, Warrior or BNK3R repeatedly (or any other boss).
Alternately Assassins can one-shot kill BNK3R due to the Bore skill being bugged; it hits him repeatedly and does insane damage with a single shot.
Just pick up as much loot as you can carry and sell it, then save & quit, rinse repeat.
At level 50 you'll be finding blue weapons worth $100k+, tons of greens worth at least $20k and maybe even some purple equipment you want to keep.
gaming.stackexchange.com/users/11920/Ben Brocka
Just go to the fridge and do this route, kill snow white parody boss, loot 2 chests in the tunnels behind her, kill the boss raider thingy from the goliath quest.
pickup everything, save repeat.
you can skip all the normal creature if you like and just kill the bosses.
This way you get to do more of them.
7k Each trip and each trip is about 3 minutes long.
Managed to farm sledges shotgun too.
Happy Hunting!
gaming.stackexchange.com/users/33497/Killerbotz
Preface: It is not necessary to farm money, one will never run out.
It's all about selling guns!
Max out backpack asap.
Sell expensive loot.
After finishing the final playthrough just farm some bosses.
I have been killing the Warrior for 6 hours now, trying to get the conference call.
In that time I have amassed 24 million by collecting purple, blue and green guns dropped.
Tip: Farm the bosses that also drop legionaries you are interested in, two birds with one stone. Have fun!
gaming.stackexchange.com/users/33714/Schottlicious
Once you beat the game, farm on The Warrior.
Be sure to have powerful guns (Repeaters, Sniper, Rifles and SMGs are recommended).
Once you make him spawn, head toward the exit but don't leave the area.
He can't hurt you there (much) and you can easily target his weak spots from there.
gaming.stackexchange.com/users/34060/Tsuki0
When farming money, equip the Pot O' Gold shield.
Its description: When damaged the shield has a small chance to drop money as well as shield boosters.
gaming.stackexchange.com/users/4797/galacticninja
Eh just cheat, dupe money with a friend its easy.
Trade him all the money you have then dash board you have to be in his game though, you can do that as many times as you want until you have 99,999,999
it goes a lot faster if you give him all your money, go to dash board so it doesn't save, load up your game so he can give you all of his money plus the money you gave him
then he dash boards so it doesn't save then join his and keep repeating its the fastest way.
Hold b to trade for xbox lol
also i know this was more for legit farming
but i just wanted anyone that was interested to know its there.
I hope people don't mind too much as it isn't really a game breaking glitch.
gaming.stackexchange.com/users/33911/Travis
There are several "badass rank" challenges that involve hoarding money or using money to buy weapons.  Where are the most effective places to farm or make money in Pandora?
Best place to farm money in Borderlands 2
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gaming.stackexchange.com/questions/84832
gaming.stackexchange.com/users/21177/Wolf
Farm money during the Mission to Save Roland. You can also try the slot machines in Sanctuary. While a common tactic to farm money, is to kill bosses, few players seem to go other routes.
Locations and missions are listed. It is suggested to farm bosses. A user is proposing to cheat.