How To Write A Price Increase Letter To Customers . Here is a price increase letter template that you can mimic to write your own: If you're stuck, look at the examples below for inspiration on how to communicate with customers. 50 Effective Price / Rate Increase Letters (+Tips) ᐅ TemplateLab from templatelab.com In a price increase letter, giving a customer an extension of the current rate is one of the easiest ways to gain their loyalty. Once in a while, the price increase is your basic right as a business. No matter what you do, there may still be a few clients that do choose to look around for a cheaper service.