Vocals for 1 song

Hope you are well. I have a song that I'll be finishing the demo in about a week to find a singer and I was wondering how much is your fee which includes leads, doubles, harmonies and ad libs? All the best,

Additional info:
I will only use the vocals for demo purposes. Not for release.. I don't have a hard deadline for this. I'm looking for a female singer. I'm an indie artist. I need all the vocals recorded (lead vocals, harmonies, stacks, ad libs). . I don't need to use your name - you can be uncredited. The lyrics and melody are already written. I just need a singer.. I'm hoping to find a good singer who can work with my limited budget.