How to make a "buy" option of a plan in joomla content

Is there a way to show single plans in article contents?

I could not find a more detailed description of of the cbsubs bot, maybe it could work via this?

Any examples?

Yes, but you'll need to substitute in its details. This can be done by using the content prepare functionality built into CBSubs as long as the CBSubs system plugin is enabled and CBSubs Content integration is installed. See the description of the CBSubs system plugin within Extensions > Plugins for details on what you can substitute in. Below is a few examples.

[cbsubs:plans plan="PLAN_ID_HERE" output="name" /]
[cbsubs:plans plan="PLAN_ID_HERE" output="description" /]
[cbsubs:plans plan="PLAN_ID_HERE" output="price" /]
[cbsubs:plans plan="PLAN_ID_HERE" output="duration" /]

Thx,
so far I noticed this possibilities to show some kind of information regarding special plans.

More specified I'm looking to promote any special plan with its image within any content.

Like , "Hey you should take the chance now to subscribe to (plan x)." Where x should be a clickable image as choosen in plans.

So, in other words, how to pick plans and place there links/images in other pages as the tab in CB?

Their images? You mean for CBSubs Plans Images and its associated field? You can't as that just shows an image for users that are actively subscribed to the various plans. Just use plain HTML and link to the plans directly for what you're wanting. You can even skip directly to the basket for that plan. Example as follows.