Labor for fixing a broken spoke is pretty ridiculous if its more than $10.

If you look a little helpless and pretty sad about it, theres a chance they could throw it in for free.

I've recevied free tightening on loose headsets and other bolts, as well as a wheel true, and a spoke straightening because it got bent for free, and i didn't even buy the bike there.

I simply looked lost and had that "I just broke something, will i ever be able to ride my bike again" attitude.

Sometimes it works, sometimes it doesn't. Usually depends on the people in the shop, their mood, and how bad the problem is.