Blake Lively Paid Over $10K For Britney Spears Versace Dress

Blake Lively didn't have to break the bank for her Britney Spears tribute ... because TMZ found out how much she paid for a Versace dress the singer famously wore back in the day.

Sources familiar with the situation tell TMZ ... Blake spent a little more than $10,000 for Britney's iconic outfit from the 2002 Versace fashion show.

We're told Blake purchased the dress through Tab Vintage, a shop in Los Angeles specializing in vintage clothing. The store posted the dress on social media, but didn't include the price -- and when Blake inquired about the cost, she was surprised ... and just had to have the garment.

Blake bought the colorful, one-strap dress about 6 months ago ... and she was waiting for the perfect moment to wear it ... breaking it out Tuesday at the movie premiere of "It Ends With Us."

Our sources say Blake made only a few minor alterations ... but she did NOT change the length. When Britney wore it, the hem of the dress reached the floor -- but on Blake's body, it ends at her ankles.

A source close to Britney tells TMZ ... Britney saw Blake in the dress, thought she looked adorable, and is very flattered -- and thinks it's a cool tribute!

Blake channeling Britney comes just a few days after we reported Britney would have final say on casting for her upcoming biopic.