The cost of mobile includes the low, middle, and high class which they are different choices to help everyone to make a decision to buy. Some buyers can pay a premium price, and some buyers look for a low price where they will pick one up to use.
In this case, In Thailand, Samsung coordinate with public telephone network, so they have the promotion which customers buy a smartphone with package and they will give free internet and the cheaper price than buying without promotion.
All of Samsung mobile and smartphone are sold for every budget access.