The percentage that the artist pays back to the label is known as the royalty rate. Royalty rates can vary depending on the artist's contract, but they typically fall somewhere between 15% and 20% of gross sales. In addition to the royalty rate, the artist may also be required to pay other fees to the label, such as production costs and marketing expenses.
So, while an artist may not have to pay anything out of pocket to sign with a record label, they will still be financially responsible for repaying the advance and any other fees that the label incurs.