底買(cheaper than HK) does not mean good for your skin.
I don't like US skin product but I buy shower gel from bath and body works which I think is worth to buy.
iS clinical, 20-30% cheaper than HK.
Kiehl's, Erno Lazio are also cheaper than HK.
Besides skincare, price of Coach and Tiffany is also around 70% of HK's.