Lady Gaga Tickle My Original Ivories for $200k

4/7/2016 8:56 AM PDT

Lady Gaga's Original Ivories On Auction Block ... Possibly for $200k

Lady Gaga's first piano is going up for auction and it's expected to fetch a small fortune ... anywhere between $100k-$200k.

That's a ton more than the piddly $780 Gaga's grandparents dropped for it in 1966. Gaga reportedly started hammering on the keys at age 4 ... and later used it to write her first song, "Dollar Bills."

The piano's being auctioned off by Julien's Auctions on May 21, and expect the price to soar. Kurt Cobain's MTV Unplugged cardigan was expected to go for $60k but ended fetching $137,500!

Some of the proceeds will go toward Gaga's Born This Way Foundation.