When user registers for the site he/she shall be presented with a set of questions like the way we do for password reset security questions, the users pick their desired questions (Admin shall have options to set no of questions, ranging from 2-5).
If the user spends more than specified time set in the admin panel for custom post types that we set (for ex jobs, events, projects , etc) A security question is popped up randomly, his access to the site is only allowed if he answers that correctly. He can take 3 chances and if he fails in all three he has to login again to the site to continue.
Budget is $ 40-50.
We have no issues in using existing plugin with mods to match this requirement.