Other than credit card tie-ins most retail outlets tend to match prices, even if they don't acknowledge it with a price-tag. So if Tesco has your model on sale this week, all other retail outlets will match the price, you just have to ask if they haven't already updated their price-tags in the store.
Which model are you interested in?
At some electronic/PC shows and fairs (Queen Sirikit, BiTEC, etc.) there can be some extra deals. But basically you have to monitor the prices, either on-line or in a mall. Samsung often have (~ once every 45 days) promotional set-ups at Seacon and other malls; right in the concourse (rather than in a shop).
I have not heard of extra discounts for volume purchases, multiple appliances at once, here but then I have not been in that situation. One thing that is nice here is free, same-day (or next-day) delivery and set-up.
Edited by lomatopo, 2011-01-28 10:57:26.