Well, it depends on the songs! If the songwriter has a contract with BMI or ASCAP you'll pay a hefty fee to the agency for permission- BMI wanted $150 a year for performances, no matter what, a few years ago. But if the song is by someone with no such affiliation, see if they have a web page, or write to them care of their cd company, and just ask. I find they're usually thrilled to share their music, although cds aren't part of my deal, just performances, and a tape that is sold to members and friends. Good luck!
Allison