Need 5 songs mastered

Hi:) I am planning to release 5 songs and am in need of a mastering engineer. What would be an approximate price for a job of that sort? Also, is there a recommended or preferred level that the mix should be at before sending it to you? Thank you in advance for your time and efforts. -Aidan

Additional info:
. I'm looking to master 3-5 songs. The song is mixed and ready to be mastered. I don't have a hard deadline for this. I'm looking to hire a top pro who's worked on hit songs, and have the budget for that.