Question

A local grocery store is advertising a discount of 20% off a large bag of peaches, which normally costs $5.

Answer 1

20% of $5.00 is $1.00 Therefore your sale price is 1.00

Answer 2

I may be wrong, but 20% of $5 is $1, right? So, it's $1. 
Here's the work.

is/of = %/100

Take what you know and plug into the proportion. 
is/5 = 20/100
Cross multiply 5 and 20 and divide by 100
is = $1
20% of $5 = $1