From F***ed in Park Slope:
8th Avenue at 8th Street. 10% will go to your local school’s PTA (because I know you all care).
Bought a big Douglass at 8th and 8th and had it delivered (free). They brought the tree in and without us even asking started to mount it in our stand. Sadly the tree trunk was way too big for our old stand but they had stands to sell on the truck and we just bought one of those (probably overpriced but saved us a trip). They set it up and went on their way. Very friendly, good service. It smells wonderful!
I second the reco for the guys on 8th & 8th. We bought a 6'6" fraser fur for $55. It's a beaut and the guy selling the trees is a character.