Do extensive research on the item you are planning to buy. Nothing feels nicer than knowing more than the seller and laughing on the inside when you know he's feeding you all sorts of bullsh*t. Trust me, spending time learning more about the item you want to buy is very very rewarding (and less riskier too)

my way of bargaining,first,act like your stupid and aint know nothin bout the stuff your buyin

second,when you know the seller is trying to con(and everybody in SGW does) you,tell them who has the higher ground and throw at him/her smart questions that makes him feel like he's/she's stupid.destroy their morale and make the conners feel like crying

then,bargain kaw-kaw till you get the price you want

a good customer in S.Wang,is someone who knows how to counter conners.my 20 ringgit