For cost you might want to check into the Idolmaker, Sweet Georgia Brown or Supercore sets.. We have had a few KJ's specifically use the Idolmaker or Sweet Georgia Brown (and Tool Box) sets to add bulk and some pretty good songs.k It's kind of hit and miss and a constant learning process. You can also request "requests" from your singers; what do they want to sing?
I also prefer Chartbuster & Soundchoice but have Legends, Top Hits, Pop Hits, etc in our books.
Susie