Prices of various car models -- ranging from entry-level hatchbacks to high-end luxury offerings -- are set to rise as automakers have announced price hikes with effect from January.Carmakers cite an increase in input costs and operational expenses as the main reason to implement price increases from the next month.Industry experts, however, note that the exercise is also undertaken by automakers every year in December to shore up sales volume in the last month of the year, as customers postpone buyouts to later months to get the new year manufactured units.