How do i get my check boxes to display and add numbers into a label on C#

Im trying to develop a form for an imaginary pet clinic and it consists of check boxes and a label. The checkboxes represent a service the clinic performs and when checked the price of the service is supposed to be displayed in the label, whenever any other boxes are checked theyre supposed to add to the price and when unchecked take away from the price. I am stuck on how i get the check boxes to have a value to display to the label

for example: the vaccinations checkbox (chkVaccinations) is supposed to cost 35 dollars

How do i get the check box to have a value of 35 and when checked to add to the label value which is zero?