Lana Del Rey Thrifted Wedding Dress Months Before Marrying Jeremy Dufrene

Lana Del Rey jumped right into wedded bliss with her alligator tour guide love, Jeremy Dufrene , in Louisiana -- and we've learned she scored her wedding dress at a local boutique months before the big day.

Sources with direct knowledge tell TMZ Lana shunned big-name designers ... instead, thrifting her dress at Vintage Market by Trashy Diva in New Orleans back in May.

We're told it's unclear whether Lana strolled into the store specifically hunting for a wedding dress, but after trying on a bunch of other stuff, she ended up falling for the dress she spotted in the window.

While the exact price tag remains a mystery -- she didn't exactly break the bank, spending no more than $400 ... which is the typical price range for wedding dresses at the store, which features curated styles from the 1920s to Y2K.

Lana was clearly getting cozy in Louisiana at the time -- just a week before her wedding dress hunt, she shared a pic chilling in the swamp with her new crew.

LANA DEL REY & JEREMY DUFRENE TOGETHER

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No doubt, Lana put that wedding dress to good use, exchanging vows Thursday with Jeremy at Airboat Tours by Arthur in Des Allemands, Louisiana, where he works. Daily Mail obtained the pics, and TMZ broke the story of the couple picking up a marriage license just days before.