Submitting a form with a payment field without processing payment

Hello

I would like to make a basic order form, but the order cannot be finalised without making modifications as the amount charged is an estimate.

For example, we sell meat by weight, but the amount varies depending on packet size. 

The problem is adding a payment field seems to take users to the payment gateway (such as Paypal) rather than submitting the results of the form to me.

That's possible using Purchase Order tool https://www.jotform.com/help/460-How-to-Create-Payment-Form-with-Purchase-Order. This does not have integrations with payment gateways so the form will be submitted normally.