It was one of my favorite online shopping websites because of their extremely low prices and big discounts. Everything (excluding books) that is sold on flipkart.com was available in letsbuy for much less (well that was before the acquisition, and now the rates seems to be leveled). But still you can get some pretty good deal on several items (if they are in stock, good luck !). I just ordered one hoya CPL filter for my camera for Rs.300 less than what is listed on most of the other e-commerce websites (and perhaps the last thing I'm buying from letsbuy). So if you are thinking about buying something other than books from flipkart.com, then do check out letsbuy.com as well.
If you have an ICICI bank debit card, you can get 7.5% discount on some items.