Commentary for Peah 8:5

אין פוחתין לעניים בגורן – when they distribute the Poor Man’s Tithe in the granary/threshing floor, they don’t give to each and every poor person less than this measure, as it is written (Deuteronomy 26:12): “that they may eat their full in your settlements,” give him according to his fullness/satisfaction.

They may not give to the poor from the threshing-floor less than a half-kav of wheat or a kav of barley. R. Meir says: [only] half a kav [of barley].
[They must give] a kav and a half of spelt, a kav of dried figs or a maneh of pressed figs. Rabbi Akiva says: half a maneh.
[They must give] half a log of wine. Rabbi Akiva says: a quarter.
[They must give] a quarter [log] of oil. Rabbi Akiva says: an eighth.
As for other kinds of produce: Abba Shaul says, [they must give enough] so that he can sell it and buy food enough for two meals.
Our mishnah deals with poor man’s tithe, the tithe given to the poor in the third and sixth year of a sabbatical cycle. As we have seen above, there is a difference between poor man’s tithe and the other agricultural gifts. Whereas the other agricultural gifts (peah, leket, forgotten sheaves etc.) are collected by the poor themselves, the field owner gives poor man’s tithe directly to the poor. Our mishnah instructs how much of the poor man’s tithe the owner should give to each poor person. He doesn’t just give all of his tithes to the first poor person that he sees. Rather he gives a minimum amount to each poor person who comes his way this way there will be tithes left over for others who come later.
The mishnah itself should be easily understood and hence I have refrained from commenting below.

דבלה – dry figs after they had been tread in a round mould [in which figs are pressed] which is called cake of pressed figs. And further, they are not sold by measurement but rather by weight, therefore it teaches [in the Mishnah] a Maneh of a cake of pressed figs, and a Maneh is a weight of one hundred Denars and a Denar is a weight of six Ma’ah and the weight of a M’ah is sixteen berries/grains of barley.

פרס – one-half of a Maneh, and in all of the measurements that are stated in our Mishnah, the Halakha is according to the first Tanna/teacher and the Halakha is according to Abba Shaul. And these things are not said other than to distribute the Poor Man’s Tithe in the threshing floor/granary, butr he who distributes the Poor Man’s Tithe in his home, distributes according to his desires and the Sages did not give him a measurement.