That would be a bad idea on many levels - you are talking Singapore.
Actually, the best deals in SE Asia are in Singapore. Go to the (in)famous alley behind Desker Road in Little India. Start from the base near Serangoon Rd. and barter with the first 3 Chinese guys you run across up the alley (they start work after dark); they work next to card tables and sell sex stuff. You should get 4 boxes (4 pills each) of either V, C, or L (Levitra) for $15 SGD total (about 360 THB). Don't be shy about walking away from the first, going to the first road, then coming back. I gave been dealing with them for years and they are straight up.