Samsung is known for putting out many devices and sometimes 'flooding the market' with their product. But their flagship devices, the Galaxy S and Galaxy Note series of smartphones have been the main focal point of the company and its sales. The S line is five years old this year, with the Galaxy S5, and Note line will be four years old this year, with the rumored Galaxy Note 4, in its probable two variants. Rumors aside, Samsung is successful, but the prices of their phones are sometimes seen as wrong. At launch, the device may invoke a 'you expect me to pay THAT for this'. As time goes by, and coming up to the announcement and release of the next model in each respective line, the discounts go up, prices go down, and you, maybe not knowing when Samsung will let loose a new device, are caught thinking 'huh, this phone is worth way more than that, but at this price, I can't deny getting it now', especially if a carrier does a two for one deal, or (and in some extreme cases) a buy one, get three free, to activate later.
Now, deep discounts are great for customers, especially if they have a lower budget than the average, or don't need (or especially want) the latest 'this' or the most up-to-date 'that', and these discounts are perfect for these folks. For instance, the Samsung Galaxy S III was, at the time of the Galaxy S IV's release, 40% less than its original launch price. The device was around $600 USD at launch, the S III, so the phone would be only $360 USD, forgetting about the carrier subsidies in the United States. The Galaxy Note II, another flagship and fan favorite from 2012 cost, at time of launch in the fall of 2012, around $700 USD unlocked, no contract. When the Note III was released in the fall of 2013, 12 months after its older brother the Note II was, the Note II cost a little more than 35% less than at launch. That means that you could have gotten a $700 phone for a little over $450. Those are real steals for such great devices, even at a year old.
The way that Samsung is able to drop prices and still make money off these one and two year old devices is astounding, but unsurprising (unlike the discounts themselves), since Samsung's devices get software updates for the full two years that most people keep the device for. This is one of the biggest draws to Samsung ant their plethora of devices.