Can I add somehow a field that would calculate prices I listed?

You may perform a calculation on your form by using a calculation widget. Please refer to the guide below:

https://www.jotform.com/help/259-How-to-Perform-Form-Calculation-Using-a-Widget

Thanks!

It is a little bit more complicated than that. I am adding one booth order ( selection of Member rate or non member rate, they will make a selection of quantity) plus Premium upgrade option (two selections possible as well)

in addition there will be sponsorship options where I will need a subtotal and a total.

I have a list of about 25 items that they can chose from, some have more than one quantity available. So it needs to include the option for a remainder?

All of these will have to be calculated.

Here is my form in current form https://www.jotform.com/build/92334438131149

Ok. In this case, you may consider setting up conditional calculations to achieve your requirement. The following guide might be helpful.

https://www.jotform.com/help/268-How-to-Insert-Text-or-Calculation-into-a-Field-Using-Conditional-Logic

For the subtotals, you may use separate calculation fields and add them again to the final total.

Please give it a try and let us know if you need any further assistance. We will be happy to help. 

I thought I had an answer but the total only works if I select only ONE item in the Sponsorship section, as soon as I select more than one, the total doesn't work... ugh so close.

https://www.jotform.com/build/92334438131149

any suggestions?