In Borderlands 4, Mad Moxxi giving away the nice legendary weapons if you know how to please her. Tipping her jar at the bar gets you unique guns that level up with you, so they’re handy whenever you pick them up. Each gun has a trick to unlock it, and learning the trick to tip can save you a great deal of cash and time.
How To Get All Mad Moxxi Weapons

If you tip Moxxi enough, she will eventually give you a free legendary weapon. Depending on how much you tip, the weapon you receive is determined, and it’s all random. Sometimes she will just be standing there with a legendary held out for you to take. It typically takes somewhere in the range of $1,000 to $30,000 in tips before she will give one, and the good news is that the weapon will always be at the same level you are currently playing at.
The Cold Shoulder is a Legendary Torgue assault rifle that always comes with Cryo damage. It’s got a built-in Hyperion shield and its shots even home in on nearby enemies. To get it, just keep tipping Moxxi’s jar in $1,000 amounts until she decides to hand it over.
The Sweet Embrace is a Legendary Maliwan shotgun that fires four shots in a square pattern. It’s not the best for hitting small enemies because of its wide spread, but it can drop with any element type. To unlock it, tip Moxxi’s jar in $100 amounts until the reward shows up.
Mad Moxxi Location in Borderlands 4

You’ll find Moxxi’s Tip Jar at her bar, Bottoms Up!, in the western part of Carcadia Burn. To get access to it, just play through the story until the mission Wrath of the Ripper Queen. During the objective called “Go to the Bar”, you’ll head straight to Moxxi’s place, and the tip jar will be sitting right on the counter in front of you.