Floyd Mayweather Stiffs Waitress After $32M Fight

Floyd "Money" Mayweather did not share A PENNY of the $32 MILLION he earned Saturday night with the waitress who served him $25,000 worth of booze and chicken wings ... TMZ has learned.

Nik Nguyen tells TMZ ... she thought she'd hit the jackpot when Floyd walked into Rehab at the Hard Rock Sunday afternoon with around 150 people. Floyd and crew ordered:

5 bottles of Patron - $2,375
3 Grey Goose - $1,425
6 bottles of Ciroc - $2,850
20 bottles of Luc Belaire Rose champagne - $11,500
1 6-liter bottle of Luc Belaire Rose - $6,500
200 chicken wings - $600
1 fruit platter - $55

TOTAL BILL: $25,305.

Nguyen tells us ... she went the extra mile to provide Floyd and company with excellent service. Not surprisingly ... the Hard Rock ended up comping Floyd, and he showed his gratitude by leaving Nguyen ... chicken bones, empty bottles and that's it.

She says it's especially maddening because some of the people in Floyd's entourage -- including Jamie Foxx -- were throwing money at random girls who were twerking on stage.

Nguyen says she's been struggling with 2 jobs and the recent death of her father ... but she didn't walk walk away empty-handed. She says security guards felt so sorry for her they scooped up a few bucks the twerkers left behind and gave it to her.

We've called Floyd's team ... so far, no comment.