If you're Resulting an Appointment with an option other than Sold, the Total Price Quoted field will show as Required. You can enter $0 in this field. It is not mandatory, although if you've delivered a quote to the homeowner, it is a best practice to enter Price Quoted.
Your company can take advantage of ReHash Campaigns to identify quoted opportunities that can still be closed. If you leave Total Price Quoted blank or enter a $0 your ReHash Campaigns will not include the Quote value.