Dougal Campbell

HeadMeta creates <code><meta></code> “description” or “keywords” tags for individual 
posts or pages. It can also create arbitrary <code><meta></code> or <code><link></code> tags. 
These are easily set on a per-post (or page) basis by simply adding Custom 
Fields.
See the Installation section for more detailed examples.

HeadMeta

Automatically add <link>, <meta> description and <meta> keywords to your HTML on a per-post (or page) basis.

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.

HeadMeta vs ADR Promotion Recommendations