I want to offer a Lifetime suscription with a Free trial to a monthly suscription. But I want the customer to decide if he wants the Free trial or not. So, I would like to have in Signup page my "Lifetime suscription product" and a second option with a bullet: "30 days Free Trial (optional) - 15$/mo after 30 days" so people can choose if they want to select the bullet of that second suscription, or leave it unchecked and skip the opportunity for the Free trial. Is it possible? Thanks.
Possible but will require signup.html template customization. Also you will need to create two separate products, one with trial and second without trial.
First you should replace select product block and create html for it yourself. Then create small javascript script that will change product_id depends on what user will select.