Always trust your eye. Shop around and compare 4. Compare the actual price you are paying, not the percent of discount. Large discounts indicate higher mark-ups. Compare quality and price together for value.
Diamond prices vary drastically with quality differences.
A cheap price is not always a bargain. Ask to see the diamond in a microscope or Dia View. A jewelers loupe is difficult to use if you are not experienced. Ask to view the color of the diamond in comparison with a GIA certified diamond. Remember a loose diamond is much easier to color grade.