Buying a diamond doesn't have to be complicated. That's the premise behind Blue Nile, the largest online retailer of diamonds, with 150,000 diamonds available on its website. Blue Nile Store deals on its certified, conflict-free diamonds include prices 20%-40% lower than its competitors', backed by the Best Price Guarantee. Use your Blue Nile Store coupons to "Build Your Own Ring" or to take advantage of everyday free shipping, the diamond upgrade program, award-winning customer service, and sales on already-discounted diamonds and fine jewelry.