The price for a fat transfer depends on several factors and varies from one practice to another. There is a big difference if you are injecting 40cc in the face or 6cc in the lips compared to 1600cc of fat for a buttock augmentation. Brazilian butt lift is so popular because it enables your plastic surgeon to transform your entire shape. Liposuction is performed over several areas depending on the individual patient needs, but typically of the flanks, abdomen, back and thighs which obviously increase the cost compared fat grafting of the lips. Many practices have some type of assistance to help with financing the procedures such as care credit.
With that said I would tell you that when it comes to your body, I would not choose your surgeon by who is the cheapest. It is important to have several consultations with board certified plastic surgeons. Also make sure that your surgery is being performed in an accredited surgery center or hospital.
Unfortunately here in Austin many patients try to save money by having their procedure performed by non-plastic surgeons and at facilities that have not been accredited and often have problems.