There's no sales tax in Delaware, and a few other states, maybe buy from a Cartier boutique in one of those places.
The point people seem to fail to mention about duty free purchases is that you don't pay duty abroad because there is an assumption you will declare the item and then pay whatever duty your country assesses. It's to prevent double taxation, not to provide you with cheap items. It's not like a "get out of jail free" card where you "save money." You only save money if you cheat on declaring or declare and are not assessed.
A price of $1,800 would have been maybe 20 to 25 years ago, not ten. I got my first love bracelet in 2008 and it was $3,600. However, a friend of mine who collects Cartier pieces found an old Cartier advertisement from I think the early 1970's and a Love bracelet was only $250. Then again a steel Rolex Submariner was also about $250 in the very early 70's and those are about $8,000 brand new today.A jeweler told me that these bracelet used to cost $1800 usd before the celebs made it popular and increased the price. Is that true? Was that like ten years ago?