Q:

How to round decimal values for specific rule

I want to use a rule in excel for specific values. 
If price>=8.40 then price should be 8.99 and if price<8.40 then price is 7.99. Meaning if decimal value is >=40 then it should be .99 with same starting digit but if decimal value is <.40 then it should be starting value -1 and then .99. Sorry if i am unable to explain my requirement. Some examples are given below.
Present price       New Price
8.40                8.99
8.39                7.99
8.41                8.99
8.25                7.99  

A:

Try this one:
=ROUND(A1+0.1,0)-0.01
Suppose the Present Price values reside in 'A' column, add the worksheet formula shown above in New Price Columns' first cell (e.g. B1) and expand it to the end of populated range. 
Note: regular Excel Round() to Integer worksheet Function typically uses value of 0.5 as a threshold for rounding up (otherwise it will round down to the nearest Integer). So, just increasing the value by 0.1 should suffice your task).
Hope this will help. Rgds,

