Thanks for your inquiry. ~ We appreciate your patience :-)
s2Member provides you with Shortcodes so you can create the Payment Buttons, or Pro Forms. You’ll pop s2Member Shortcodes into a Post or Page and then link your visitors to those pages where the Shortcodes exist (i.e. where the Payment Button or Pro Checkout Form is located).
How you integrate these Buttons/Forms, would be completely up to you. If you’d like to create a drop-down menu on your site that redirects people to certain Posts or Pages based on selection, or if you want to show/hide certain Payment Buttons on a Post or Page, based on something like this, you will need to custom code that.
This is generally accomplished using a couple lines of JavaScript and the onchange event handler attached to SELECT menu. You can search the web for examples of how to create something like this. Some users in our Community Forum have also posted some examples, so you might try searching there as well.