Tough question. Millenials or anyone else seeking to purchase an engagement ring should at least be minimally versed in the 4 cs. Cut, color, clarity and carat weight. The diamond engagement ring market today is incredibly competitive. Dealers are aware that todays consumer is far ore knowledge than in the past. Unrealistic bargains such as 80% off are ridiculous80% off of what!? By com-paring the attributes of a diamond as much as possible, a basic idea of an ideal range can be determined but comparisons to like kind and quality diamonds is crucial. Comparing different overall qualities or lab certificates which state the same characteristics to other lab certificates can create a totally false impression In my experience most private jewelry companies, online internet services, and chain organizations strive to be extremely competitive with educated customers. The key is not purely price although this is an important factor, but to find an organization that one has trust and confidence in. I would definitely suggest purchasing an engagement ring form a company that allows you to have an independent professional appraisal in addition to the stores insurance replacement description and valuation. Finally I would limit my search to three or four at the most sources since confusion and exhaustion usually sets in which defeats the entire purpose. Many customers in their hast to get a good deal miss out when passing up a diamond that really seems the best.