10 years ago I paid $125 for mine in Angeleton, Texas, but she was a used baby. Decals are faint, case is worn, but as my mechanic said, she's a fast sewer! I would guestimate anywhere from $250 to $500...maybe split the difference-$$350 to $375?
Or if she's a very dear friend and wants you to have it and money is not so much of an object, towards the lower end.