“Actually prince cut diamond is less expense than the round at the same carat wt. Its not the cut that ultimately determine the price it is the grade of the diamond. The more clarity the higher it is. Meaning. You can get a princess cut diamond for $300 but it has impurities (visible cuts cracks along the stone and faucet–which affects the brillance (shine)) So you want to tell your friend to sit down with a jewler at a store and have them show with the scope the differences in the stones. Also, tell your friend to take in consideration the activities she does, because there are different prong settings. The price is also affected if you’re going to get the ring it self in yellow gold 18k or 21 or white gold (which needs re dipping atleast every one to two year in rhodium because there no such thing as white gold) or platinum which is sturdy material but is less shiny and needs to be buffed more often because lack of scratch resistance. One more thing. Be sure he takes in account the seasonhe is getting the ring. If he’s buying it now in the winter months and giving it later. Fingers tend to be smaller in cold seasons than in warmer.”