I was just thinking that may be we should compile a list of shops who cheat their customers through their negative tactics. So that people who go there in future may be kept from getting cheated.
In my case I became a victim as well, I went there to buy a digital camera Cannon IXUS 960IS. Before going there I visited some forums and came to know that one should know very well what he is going to purchase and should not believe in the sales guys in their recommendations for alternatives. So I did my research and knew very well about my product and what is included in the package and usual price. The usual price was 600SGD at other places in small shops and it was 699SGD at big shops like best denki etc.
I went to sim lim and visited different shops, finally I went to this shop... I asked the person for the price inclusive of GST, I mentioned explicitely again that it should be including GST. He called someone and told me 535SGD, I confirmed what is in the package and he told me the right things including 1 year warranty. I asked him that okay I wanna purchase, then he said that you will have to pay the GST as well and it will be 570

After reaching home I visited the cannon website and came to know that they had a promotion with this model i.e. digital kit bag worth S$30, and photo printer worth S$220, and 4GB card probably worth S$50 (only this card was given to me by the sales man). I was happy to know about this promotion and was planning to go to cannon dealer to claim it, but then I say my warranty card and it was already stamped as "REDEEMED".
So I think this was the dishonesty on sales man's part he should have told me about it, he gave me discount of 30S$ but infact charged me S$250 extra.