Restaurants will give you free food to join their loyalty programs, during your birthday, and sometimes just because. Companies will also ship you free food samples. You can find both types of freebies here.
Enter the code "LUCKYWHOPPER" on the Burger King mobile app to get a free whopper from now through 6/2! You may be able to use this offer multiple times based on some other user's statements.
McDonald's is known to be affordable, but somehow it tastes even better when it's free. There are lots of deals and rewards to enjoy via the app, and there are also special events every year.