You can find really good prices on them. I live in the midwest and they go anywhere from $200 to $450. It just depends on how old they are. Singer started making them during the 1930s depression and they continued making them until about 1960 or so. The earlier ones had a fancy faceplate and are worth much more as a collectors item. The later ones could be white, tan, black, or even a pale mint green. They are all workhorses. I think it boils down to how much you are welling to pay and how lucky you get! :-D
Have a joyous holiday season.