Simply replace the unfilled areas such as "" and "[date]" with your information.
Your satisfaction is important to us. In order to continue to produce a high-quality [product/service], we have needed to recently upgrade our equipment. This cost along with constant inflation has forced us to increase our prices. Enclosed is a document explaining the price increases in more detail per product.
Thank you for your understanding in this matter. We feel that these increases will still allow you to sell our products at competitive prices.