One Roti and so many advantages :-
Can fill Your stomache and give You Strength.
If Given to a Beggar then one can receive Blessings in return. 
If given in small pieces to ants and Fishes it would strengthen your Sun.
If given to Cow then You can strengthen Your Venus.
If given to a Crow then can strengthen your Saturn.
If given to a Dog then can strengthen your Ketu...
( So Donate at least One Roti everyday minimum. It does not cost much but the advantages accrued are innumerable. And what we call as 'Donation' is actually Not so. Because in return we get 'Blessings' So its a 2 Way Profitable act for us to Donate).