Do you know when, and when not, to give away products?
You shouldn't charge a client for using your own product as part of the toolkit you take (e.g. we use Upsizing PRO when doing an upsizing job). This is because it's just like a plumber using his wrench. You take it away with you when you leave.
However, you should charge clients when you install or provide one of your products for the ongoing use of the client e.g. Code Auditor, Link Auditor, etc. which the client's staff will use after you leave. This is just like a plumber buying a particular piece of pipe to fix a sink.
Generally, you should avoid discounting product prices to clients since this would devalue the product.