Assuming your table is build this way: A repeatable row named "Row" with a Price field and a Subform containing a radio button group which can have either the value 1 (yes) or 2 (no) …

… the calculate event of the Sum feld can could be:
// Select prices only form those rows, where the radio button selection is 1
var oCells = Table.resolveNodes("Row.[Subform.RadioButton eq 1].Price"),
iSum = 0;
// Add all found prices together
for (var i = 0; i < oCells.length; i += 1) {
iSum += oCells.item(i).rawValue;
}
this.rawValue = iSum;