I want to add functionality into my site that users may be able to sign agreement, pay, and then submit I want to add functionality into my site that users may be able to sign agreement, pay, and then submit. Also I would like to use this data in the future...
Any advice??
EDIT: I want something like web form with payment option on it, I just want a user to be able to pay via Credit card, if the form is filled correctly and all required fields are good... Don't need HIGH-END commerce or online store ??? Please help :(
You can use the Webform module to allow the users to fill it out and then use the Payment for Webform module for payment options.


  This module provides a payment reference Webform component, which
  allows users to associate payments (made through Payment) with Webform
  submissions. A possible use case is requiring users to pay before
  submitting a webform.


or you can do it with Commerce Webform module, by following this tutorial you can easily set up the payment options.