Mr. Kuchchal,
Thanks for conveying legal aspect.
However In that case Shop owner should have immediately either removed it from the Shelf,or mark "ALREADY SOLD" so as to avoid problems.
In foreign countries, Even by mistake if an article is tagged at lower pricetag (during Sale period) and after that the offer of discount is withdrawn (because of Sale period is over) and price restored to original price. Which was more , Store has by mistake forgotten to remove the old tag and consumer presants it to the counter, he is charged the discounted old / lower rates.
Bhasker Parikh