How we change what others think, feel, believe and do
We find round numbers easier to mentally process and accept than more complex numbers. For example 20 is just a bit easier on the mind than 19 and more so than 19.99.
When prices are the same as a coin or note, this makes it easier for customers to hand over the exact price, without the hassle of dealing with change.
A store uses 'everyday pricing' as a brand, rounding prices to whole numbers, mostly using multiples of five and ten.
A company uses round numbers for its price range, with clear multiples between separate products and ranges.
A store has a range of $1, $5 and $10 products that match note values, making purchase very ease.
The basic principle of round numbers is one of ease. It is easier to think about a simple number than one that is more complex, and hence easier to say yes to it. When matched with a coin or note, and where customers are more likely to have this money, it further eases the purchase.
Rounding numbers contradicts the very popular 99 Effect, where pricing such as 19.99 may be seen as being significantly less than 20.00. It may also be argued that the cognitive effort of 19.99 could make people not try to quantify it, which can make them accept it more easily (or perhaps reject it).
Another consideration is around the Unique Number Pricing effect, where people may assume that an unusual price is more honest, being based on actual costs with a simple addition for profit. Against this, most people are fully aware of the deceptive nature of the 99 Effect and other variations, and may see round numbers as more honest.
When considering which approach to use, consider factors such as: