Landed a big-ticket corporate party. The event organizer's contract stipulates that I need to provide a certificate holding them and their client harmless.
After letting my fingers do the walking, I found the following:
CDSS: $65 membership, $50 for insurance, additional fee for each certificate
CallerLab: $105 membership (includes licenses for contemporary music), $25 for insurance
NFO: $30 membership, and insurance is included. (They don't make this clear on their website.) Home Page National Folk Organization
I hope this helpful to someone.