Where are you located ? IMO this trend diamond plate on amazon UK is an incredible value: https://www.amazon.co.uk/dp/B004RZJ0F0

It's 35£, which comes out to <50€ shipped in Europe. It used to be 120€ here and it's 113USD on amazon.com

This and a leather strop with some compound is all I use to sharpen all my chisels/plane irons (with a honing guide). I sold my 2 DMT plates for 100€ and bought this instead.