Shopping online provides you with all of the sales that the store provides, sometimes more and you never have to deal with the crowds. Places like walmart.com and target.com offer the same sales and you dont have to worry about things being in stock like in the store.
Mandyloo gives excellent advice with shopping online. If you prefer store shopping, I find a store that is open 24 hours is great to shop at 2-5 am. The place is pretty well empty, yet all the great sales are there.