Timo Schlueter

TagMeta generates meta keywords using your most used tags. 
It automatically gets the 10 most used tags out of your 
blog posts and pages and puts them into a valid meta- 
keyword string. This string then appears in the header of 
the home page of your theme. If you want to add tags per 
post, i suggest youre going to use the Headspace plugin.

TagMeta

TagMeta generates meta keywords using your most used tags.

gguo01

ADR Promotion Recommendations is a simple plugin that displays promotion recommendations based on page content. Highly relevant promotions are displayed automatically right below your post content. You can also drop it to your sidebar as a widget.
To display promotions, you need to register your site and email contact. Please go to https://www.adrelevantis.com/wp/plugin-register.php for details.

ADR Promotion Recommendations

This plugin displays relevant promotion recommendations below post content and allows you add them in sidebar as a widget.

TagMeta vs ADR Promotion Recommendations