DJ Real Sole's only known song is New You, four variations of which can be heard in the shops in The Galleria:
Ammo Knights version The Ammo Knights version has a marching beat as well as sounds reminiscent of a military radio and a bugle horn, referencing Sheldon's obsession with the military.
Headspace version The Headspace version is very calming and has high vocals, mirroring Flow's chilled personality and the fact she sells headgear. It also has sounds of a ukulele and maracas, referencing to her characterization as a hippie.
Shella Fresh version The Shella Fresh version has a rock sound, mirroring Bisk's look of a rock fan as well as his slang. It also has more emphasis on the bass, referencing the fact he sells shoes.
The original can only be heard in-game via Jelfonzo.
Trivia
Sunken Scroll 6 in Splatoon 2 shows a picture of Bisk and a music sheet of "New You" , hinting that he may be DJ Real Sole.
The Sole part of DJ Real Sole, is the bottom part of a shoe, further hinting he is DJ Real Sole as shoes are the kind of gear he sells.
Sole is also a type of flatfish, so this may just be a fishy reference.