[REQ] WP Plugin for "Locked Contend" or sell digital products

Hello together,
I'm looking for a plugin to lock special content.

For example I write and publish an article in my wp blog. The user just see an short introduction of this article - he rest of the content is locked. If the reader like the introducing content and want to read the full article there is a possibilty for payment (paypal, credit card). so he click the payment button and comes to PayPal (e.g.) automatically. After payment he comes back to the blog an see the complete article.
optional he get an email with download link of a pdf document. I hope U understand what I need in detail?!!!?!?! Do U have some recommendations for a helpful plugin? Pro paid version is no problem.... Just it has to work!!!!

Best wishes and thanks in advanced

To do that you'll need to be a real authority, people will not pay unless they feel you have some weight in the niche. You can ask them to pay with a like instead, so they have to like to unlock. You can get a free plugin from WordPress here https://wordpress.org/plugins/wplike2get/

Not sure on that one however another option would be to lock the content and having the viewer opt-in with their email to unlock it, good way to build a following, and send offers down the road. The plugin 'Thrive Leads' lets you do this. https://thrivethemes.com/thrive-leads-content-lock/