The treasury, in the days of Jesus, is a place located in the Women's Court that was in the temple area but was not part of the temple itself. Women were not allowed in the temple, so the fact that this widow was casting her offering into the treasury tells the location of the treasury.

Jesus used an instance to teach His disciples a very important lesson. He did not say these things to the widow personally. God's promises concerning giving, gives us  assurance that the offering was blessed back to the woman in her life, but the widow did not hear His comment. There is no indication that the poor widow ever knew that anyone recognized the extent of her sacrifice.

There are times when we may feel that no one knows or appreciates our sacrifices. But, just as surely as Jesus saw this woman's giving and knew of the sacrifice involved, God takes note of our smallest deeds and one day, will reward us openly.

The Lord does not judge the size of our gifts by how much we give, but rather by how much we have left over after we give. 

People tend to compare themselves with each other but the Lord doesn't judge our giving by what others give. He judges our gifts by what we have to give. The Lord looks at the heart of the giver more than at the gift. 

When we stand before the Lord, all of our works, not only our giving, will be tried to determine what sort, not what size they are.