system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do we still do $0.99, or $49.99, and not just round up that penny? Why did we start this in the first place, and do other countries aside from the U.S. do this?
gpt
Marketing. People are more likely to buy a product with ending in 9 as the human brain only comprehends the first number effectively. A $49.99 reads like it’s $40, even though we know it’s $50. Psychologically, it drives more sales for the business.