Big box retailers should discount everything. That blue cardboard box at Tiffany's has cost some guys hundreds of thousands of dollars http://www.walletpop.com/2011/04/09/in-the-market-for-a-million-dollar-diamond-ring-try-costco/
Your wife/fiance/girlfriend will expect you to buy a "rock" that's twice as big. You will not save any money. :eek: