Android food menu checkbox

Looking to do a simple beginner food menu app on Android using checkboxes. I have 3 Strings (Burger $5, Pizza $4, Hotdog $2). I used the 3 strings to make 3 checkboxes and I would like to get the total price once I mark the checkbox of each item. So if I click Burger and Pizza, it will display $9 as my total.

My question is: I have the strings.xml for the checkbox text as "Burger $5", "Pizza $4", and "Hotdog $2". How do i get the total price from this?

Thank you and sorry if its a simple task, but its the first project I'm working on.