install adobe flash player without subscribing to stock 30 day offer

We give Flash Player away free of charge, but we do use the opportunity to market our other products and services.

That said, those offers are typically presented in a browser window that gets spawned on completion of the Flash Player installation.  If you're seeing the offer to sign up for Adobe Stock, you probably finished the installation successfully.

What I'm getting based on your question, is that you ran the Flash Player installer, but the thing you were trying to fix by installing Flash Player still isn't working.

To give you any useful advice, I'm going to need to know more about your computer and browser, and the problem you were experiencing:  https://forums.adobe.com/thread/1195540