coding Add price options to a form that will add to cart

[PreciousU]

so I am looking for a code to add to the contact form that will provide a drop down option to select a monetary amount. Also how would I change the coding of the submit button to add the amount to cart?

 <input type="submit" class="btn" value="{{ 'contact.form.send' | t }}">

[KetanKumar]

@PreciousU 

sorry its not possible to add price option in cart page