Hello Rakesh,
This isn’t possible with s2Member by default, it is however easily attainable with custom code.
You would simply create some checkboxes with our products, which would have the value of how much they cost, then when the user clicks an image (not a button, but the image a button uses) he will be redirected and it will pass through a simple code which will do all the math for what the user chose, and will create the correct button depending on what math function came up with, and will give him the correct levels or ccap, then it would correctly redirect to the URL the shortcode outputs.
It’s not too complicated if you know some PHP, it’s actually a good practice project.
Hope this helps. :)