Pricing
Tactic
Offer Discounts With Low Right Digits
The difference between $22 and $23 seems more significant than $28 and $29

Overview
Small digits can enlarge a perceived gap:
...because 3 is 50% greater than 2, and 8 is 14% greater than 7, the absolute difference between 2 and 3 is perceived to be greater than that between 7 and 8, even though their absolute differences are identical. (Coulter & Coulter, 2007, p. 163)

- Coulter, K. S., & Coulter, R. A. (2007). Distortion of price discount perceptions: The right digit effect. Journal of Consumer Research, 34(2), 162-173.