Hi guys

my question is straightforward and simple.

When retailer (like Wal-Mart) wants to put some product (say DVD
Player) on-Sale, How he can decided how much "Off" he should give to
customers to increase X percentage of sales/customers/profits etc.

Like What would be the impact on overall profit or Sales when i put
product X on 50% and what if i place it on 75% Off.

Furthermore, i would like to know the exisitng models (Mathematical,
Literature, Theoratical) to plan the "Sale-Price" for particluar
product.

I am interested in any retail store products as an example.

Looking forward for quick response

I understand that a lot of the Special Offers are funded by the manufacturer.

It also varies greatly from product to product.  I rarely see cars for
sale for more than 15% less than retail, yet jewelry is rarely less
than 60% off at any store.
If you've ever shopped at Khol's, you see that 75% of the items in the
store are "on sale" when in reality the on sale prices are more
realistically their normal prices.

And another example of how sales are used; Grocery stores will send
out sale fliers advertising 50% off of selected items knowing that
people who come in for the sales will stay and buy other goods.

Something to keep in mind when you offer a sale is; How many people
who would have bought the good from you at full price will buy the
good cheaper because of the sale?  That is the real cost of a sale (as
long as you're not selling at a loss), and any extra sales (profit)
you make first must make up for your loss... then additional sales or
repeat buyers you obtain due to the sale are the benefits.