Problem:

We want to calculate the reduced price corresponding to each full price in column A.
The result is to be included in the following output string: \"Reduced price is $XX.XX\".
Price reductions are calculated as follows:
80% of full price for prices over $80.
90% of full price for all other prices.

Solution:

Use the CONCATENATE, TEXT, and IF functions as shown in the following formula:
= CONCATENATE(\"Reduced price is\", TEXT(IF(A2>80,80%*A2,90%*A2),\"$00.00\"))