Cbsubs: Pass a variable inside a plan and make a Post request

That's the point I don't need a digital store but just to add one product with some options nothing more. Use an heavy component such Virtuemart or any other addon like this is not ideal.

Now I wondering if is possible to insert in Product description a CB tab which could contain Ajax field could do the job..Like that no need to edit profile. Then after payment I could clear data with a trigger/action for re-use the same product where user could later buy again the product by introducing different data.

any clue ?

Adding inputs to the description won't do anything. You could try extending the functionality using triggers. I do know it's possible through API as CBSubs Promotion does it to add the coupon input. Taking a quick look at CBSubs Promotions you'd probably use onCPayEditBasketIntegration or onCbSubsAfterPaymentBasket trigger to add new HTML to post with the form. You could use a code action to echo your new inputs using CB Auto Actions to see what happens.

Ideally we'd like to have field management for CBSubs so plans could have custom fields shown during the purchase process. I just can't provide any details about this, because we have only discussed it briefly. We also have our options plugin that lets you have multiple prices and durations per plan, but it's not ready to be upgraded and released yet (maybe built into next major CBSubs release, I don't know at this time).