Ability to know the total sales in a form within a time frame.

I am wondering if you offer some kind of totals tracking type feature?  I'm thinking, if I put in dates, if it would add up my total sales for the dates listed or something?  Does such a thing exist?

I think that this could be achieved by download your submissions data as an Excel file, here is a guide that will help you with that: http://www.jotform.com/help/44-How-to-Export-Form-Data-to-Excel.

Before to download your submissions you would need to select the time frame, to do this you only need to click on  the gear icon, then select the time frame as shown in the image below: 

This is only an option, it will allow you to get the submissions data for that time frame and it will allow you to see the total of each submission, other way would be creating a Visual Report, but this option will allow you to show the total of all your submissions, here you are not able to select a time frame, here is the link to the guide with more information about this feature: http://www.jotform.com/help/187-How-to-Create-a-Visual-Report-with-your-Form-Submissions. 

I think that will submit a feature request, since I can not find a tool to achieve exactly what you need, we will inform you if this is available. 

The problem is that I can't use the sum feature in xls because there are so many other details in the same field that shows each order total. 

Yes, there are other details that do not allow to use the function in Excel, an option would be that you add a Form Calculation widget, you will find it on this link: http://widgets.jotform.com/widget/calculation. 

This guide will help you to add the widget to your form: http://www.jotform.com/help/252-How-to-Add-a-Widget-to-your-Form. 

Once it is added you only need to include the payment section and it will calculate the total:

It should get the same total as the payment integration and it will contain only the number instead of the payment details of the payment field, I think this could allow you to use the sum function in Excel.