Brandi Glanville is auctioning off several outfits she wore during her stint on "The Real Housewives of Beverly Hills" ... 'cause she needs cash amid her intense medical challenges.

Brandi tells TMZ ... she listed several 'fits she rocked on the Bravo series on eBay for two important reasons -- she very much could use the dough ... and the clothes are just too damn triggering.

So far, BG has nine outfits listed on the site ... with bids starting between $500 and $1,000 ... and she tells us they need to sell sooner rather than later.

As you know, Brandi has been battling a mysterious condition ... and she's has been in contact with medical professionals -- including famed plastic surgeon Dr. Terry Dubrow -- to help her overcome her facial disfiguration.

And all that ain't cheap ... Brandi telling us she's been living off her savings for two years now ... and needs this extra income to help with all her bills, especially the medical ones!

Getting rid of the clothes will also be good for her mental health, with the reality star saying Bravo "ruined her life" ... which she's reminded of every time she opens the closet.