If a gallon of milk normally sells for $3.79 and you want to have a sale selling a gallon for $3.50, you don't jack the price up to $7.00 a gallon then have a 50% off sale.
Kroger does it around here all the time. Buy 1 get 1 free, means the price went up at least 80% right before the sale started!!!!
Consumers are dumb some times. I heard a Kroger clerk say that Krogers could take an item that is normally $.59 and sell twice as many when they put it on a 10 for $10 sale. For some reason, buyers go nuts on that sale.
Worst are the "Going out of business / Clearance sales" Some outfit buys out a closing store's inventory at a discount, jacks up the prices 30+%, then gets customers to think they are getting a great deal at the initial 25% off everything!
It'll be 2 months slowly dropping the percentage before they offer prices that are actually better than normal sale prices.