Lab diamonds are getting cheaper every day - they use subsidized energy in china and India, and are already trading for $30-$50 per carat wholesale. Sure, retail prices will always be higher than wholesale - but current retail prices are 2000-4000% which is unheard of for any retail product (apart from visine which retails for $2500/gallon - look it up).
Price shop online - ecommerce and B2C websites will always be cheaper. Even if you prefer to buy in store - show the printouts of online prices because even those only retailers have at least a 1000% markup. Even if you dont care about the resale value why pay thousands extra for something that is worth basically nothing already?
Attached is a wholesale price list with current prices per carat - this is what retail stores are currently paying.
Note - i am not a vendor and not selling anything - just came across this from a friend who is in the business and think a lot of people dont realize how high the markups are here.