Wordpress plugin / Custom function

I'm developing a website on Wordpress. I'm a young web developer and need some help with a plugin I purchased. I would send it to you. The current plugin protects each of the comments that are approved on the post. You add the correct password that the admin added on the "Post Submit Box" on the post editor in the administration and cross checks if correct. If correct, the function allows the user to see each of the comment that are password protected. I want the current plugin or the new one -if you decide to do so- to: - be able to password protect all the comments of that post. By that I mean that the comments are not visible when active only a password input field is visible under the post. Structure: 1.Post. 2. Input password field that allows -if it has acorrect password- to see the comment form and rest of comments. If the user correctly adds the password the user should be able to see the comment form and the rest of the comments. My budget is 30$.