Any good lipo and bbl doctors in New York with reasonable pricing under 6-7k?

Take great care when price shopping a Brazilian Butt Lift procedure. There are many components to the procedure and a reduced price often means reduced results or, even worse, medically dangerous procedures.
Be sure to consult with board certified plastic surgeons who have extensive experience with fat grafting procedures to discuss the surgical techniques for harvesting (liposuction), processing, and re-injecting the fat. Surgical technique during each step of the procedure, along with your adherence to the post-op instructions, will determine the success of the procedure.
When price shopping this particular procedure, you are very likely to be comparing apples to oranges.

dear Patient:  any Board Certified Plastic Surgeon would be charging at least $6,000 for two areas of Lipo and Fat Transfer to the Buttocks.  Please be sure to ONLY consult with Board Certified Plastic Surgeons that are certified by the ASPS (American Society of Plastic Surgeons). You can go to the ASPs website and find a doctor in your area! Please take care of yourself.....the lower price tag means surgeons are cutting back on essential services like a Board Certified Anaesthesiologist or Operating Rooms that are not up to standards! Please take care! And hope this helps 

Price should not be the deciding point when choosing a Plastic Surgeon, I dont think you will find one in that range in NYC, try looking abroad, and choose one that actually knows what is doing and have all credentials on point to perform a Plastic Surgery. Best of luck ,