What are the ramifications of "ve'Cheilek Lo Yih'yeh l'cha be'Socham"?
Rashi: It disqualifies the Kohanim from receiving a portion in the spoil that Yisrael capture from the enemy. 1
Ramban, Targum Onkelos and Targum Yonasan: It implies that, not only will the Kohanim not receive a full portion in the land, like any of the other tribes, but that they will not receive even a small one.
Refer to 18:20:151:1 and note.
Why are the forty-eight towns of refuge not counted in the Matnos Kehunah?
Ramban: Because they were predominantly intended for the benefit of Yisrael. 1
As their name suggests.
What are the implications of "Ani Chelk'cha ... "?
Rashi (in Shoftim Devarim, 18:2): It explains why the the Kohanim do not receive a portion in Eretz Yisrael - because Hashem is their portion, and they receive all their needs directly from Him.
Ramban (citing the Sifri): It implies that the Kohanim will eat at Hashem's Table. 1
With reference to the Korbanos, which are brought in Hashem's House and eaten there.
QUESTIONS ON RASHI
Rashi writes that the Kohanim have no portion in the spoils. But Elazar (and the Kohanim and Levi'im) received a Terumah of the spoils from Midyan?
Riva: "be'Artzam" earlier in the Pasuk extends to "ve'Cheilek Lo Yih'yeh l'cha," 1 implying that it is only in Eretz Yisrael that they have no portion.
Oznayim la'Torah: That was a Hora'as Sha'ah 2 - a momentary ruling issued by Hashem for that occasion only. Moreover, the spoils were given to them indirectly in the form of a tax.