How to use a WHILE loop until all values in a column to be zero? pl/sql

For example, let's say that we have kids table and candy table .

create table kids( kid_name varchar2(20), money number);
create table candy( candy_name varchar(20), price number);

And I want to create a procedure(sales) that will make a sale for a random kid_name buys a random candy_name. In every sale kids money are dicreasing until all kids money := 0. How can i express it with while loop?