Mass of the object remains same every where.
g = G M1 M1 / d²
M1 and M2 are masses of the bodies. d = distance between Earth center and the person on the surface.
The distance d is less at the poles. So the gravity g’ is more at the poles than at the equator. Now, the gold bought at the poles reads W grams weight. The mass of the gold purchased is W/g’ grams.
The gravity at the equator is g. The weight = W/ g’ * g = W * g / g’ .
Since g < g’, the weight will be < W. So the weight of the gold as shown by the machine at the equator will be less.
So the person will have paid more at the poles. Same mass of gold will cost less at the equator.