1)
(a) The Mishnah forbids selling Ma'aser Sheni outside Yerushalayim, even on condition that the purchaser takes the fruit to Yerushalayim (see Tiferes Yisrael, end of note 1. See also Tos. R. Akiva Eiger) - because he holds that Ma'aser Sheni is Kadosh.
(b) The author must therefore be Rebbi Meir.
(c) Beis-Din may not take Ma'aser Sheni as a security, nor may the owner give it as a security against payment for goods or against a loan (Sh'nos Eliyahu) - because the Torah uses the term 'B'rachah' in connection with it.
(d) The Tana also forbids swapping Ma'aser Sheni for Chulin or using a Ma'aser Sheni coin as a weight ...
(e) ... the latter - because it is considered a denigration of the Mitzvah.

2)
(a) The Tana now forbids someone who has Ma'aser Sheni wine in Yerushalayim itself, to swap wine for oil or vice-versa. In spite of having already taught us this with regard to Ma'aser Sheni outside Yerushalayim, he nevertheless needs to repeat it with regard to Ma'aser Sheni in Yerushalayim - since there is a concession to acquire food and drink with the money of Ma'aser Sheni (which is forbidden outside Yerushalayim).
(b) And when the Tana extends the prohibition to other fruit - he is referring to fruit other than corn, wine and oil, which are only Ma'aser Sheni mi'de'Rabbanan.
(c) One is permitted to invite someone to one's house to a meal consisting of Ma'aser Sheni.
(d) One may not however. give it to a friend as a gift, according to those who hold 'Matanah ke'Mecher' (see Tos. Yom-Tov).

3)
(a) We learn from the Gezeirah Shavah "Lo Yimacher ve'Lo Yiga'el" (by Charamim) "Lo Yiga'el" (by Ma'aser Behemah) - that, not only can Ma'aser Behemah not be redeemed, but (like Charamim) it cannot be sold either ...
(b) ... neither alive nor Shechted, neither unblemished nor blemished.
(c) The Tana says 'Tamim Chai' - because of the Seifa regarding Bechor, where there is a distinction between Tamim Chai and Tamim Shachut.
(d) The Basar of Ma'aser Behemah ...
1. ... Tamim Shachut - is eaten by the owner in Yerushalayim.
2. ... Ba'al-Mum Shachut - is eaten by the owner anywhere.

4)
(a) The owner of ...
1. ... a Ma'aser Behemah animal - is forbidden to betroth a woman with it (just as he is forbidden to sell it).
2. ... a Bechor (who is a Kohen) - is permitted to do so ...
(b) ... just as he is permitted to sell it ...
1. ... alive and unblemished (but not Shachut [see Tos. Yom-Tov]) ...
2. ... blemished, either alive or Shachut.
(c) The basic principle that governs the distinctions between Bechor and Ma'aser Behemah is - that whereas Bechor belongs to the Kohen, Ma'aser Behemah does not belong to the owner.
(d) The sole case where the Din of a Bechor is the equivalent to that of Ma'aser Behemah is - Tamim Shachut (in the time of the Beis-Hamikdash), both of which are eaten by their respective owners in Yerushalayim.

5)
(a) To redeem Ma'aser-Sheni, one needs - a minted coin.
(b) The Tana learn from the Pasuk in Re'eh ...
1. ... "ve'Tzarta ha'Kesef be'Yadcha" - that a coin with which one redeems Ma'aser Sheni must be minted ('Kesef Tzurah').
2. ... "ve'Nasata ha'Kesef be'Chol Asher Te'aveh Nafshecha" - that the coin must be in circulation (i.e. it must have purchasing power [see Tiferes Yisrael]).
(c) When the Tana concludes that one may not redeem with money that is not in one's possession - he is referring to a case where the owner's purse fell into the sea, and divers must be hired to retrieve it.

6)
(a) The ideal thing to do with one's Ma'aser Sheni money in Yerushalayim is - to purchase with it Shelamim ...
(b) ... which we learn from the 'Gezeirah-Shavah' "Sham" "Sham" from Har Eival.
(c) The Tana rules that the skin of a Shelamim animal or of a Chayah that one purchased with Ma'aser Sheni money - goes out to Chulin (see Tos, Yom-Tov) and can be taken out of Yerushalayim.
(d) We might otherwise have thought - that one needs to redeem it and purchase with the proceeds food to be eaten in Yerushalayim.

7)
(a) The Mishnah rules that closed barrels of wine that one purchased with Ma'aser Sheni money - go out to Chulin (provided that they are customarily sold together with the barrel).
(b) Neither the skin of the Shelamim nor the barrel in which the wine is sold will go out to Chulin - if the seller or the purchaser is a tanner or a potter (respectively), because then the skin and the barrel is not sold merely on account of the animal and the wine, but in its own right (in which case it adopts the 'Kedushah' of Ma'aser Sheni and must be 'eaten' in Yerushalayim).
(c) The shells of nuts and almonds that one purchased with Ma'aser Sheni money - go out to Chulin.
(d) One cannot purchase Temed (wine-dregs [see Tos. Yom-Tov]) before it has turned into sour and become vinegar - because then it is considered water, which cannot be purchased with the money of Ma'aser Sheni (see Tos. Yom-Tov).

8)
(a) The Torah permits the purchase of Chulin animals with Ma'aser Sheni money ...
(b) ... only the Chachamim forbade it - because they saw that everybody was purchasing Chulin, instead of adorning the Mizbe'ach with Shelamim (as the Torah intended).
(c) If someone uses Ma'aser Sheni money to purchase a Chayah as a Shelamim or a Behemah as Chulin - his sale is invalid ...
(d) ... and when the Tana says 'Lo Yatza ha'Or le'Chulin', he means - that it is outside the realm of the category of animal whose skin goes out to Chulin.

9)
(a) The Mishnah rules that if someone purchases ...
1. ... open or closed barrels of wine where one normally sells them open - the barrels do not go out to Chulin; and the sames applies to ...
2. ... baskets of olives or grapes, which are normally sold together with the basket.

10)
(a) Basically, we learn from the Pasuk "ve'Nasata ha'Kesef be'Chol Asher Te'aveh Nafshecha, ba'Bakar, ba'Tzon, ba'Yayin u'va'Sheichar u've'Chol Ashar Tish'alcha Nefshecha" - a 'K'lal u'P'rat u'Ch'lal', that one can only use Ma'aser Sheni money to purchase things that are similar to cattle, sheep, wine and strong wine.
(b) This precludes water and salt - which are not 'fruit from a fruit and do not grow from the ground (see Tos. Yom-Tov).
(c) We also learn from here that there are times that one cannot even purchase fruit either, such as fruit that is attached - or even fruit that has been detached but will go bad before it reaches Yerushalayim ('Eino Miskayem').
(d) In the event that one does purchase any of the above ...
1. ... the fruit - remains Ma'aser Sheni.
2. ... the money - Chulin

11)
(a) In a case where someone purchases fruit with Ma'aser Sheni money outside Yerushalayim be'Shogeg - which means without realizing that the money is Ma'aser Sheni money, the sale is invalid.
(b) In the equivalent case, but where he purchased the fruit be'Meizid ...
1. ... (when the Beis-Hamikdash is standing) - he must take it to Yerushalayim and eat it there.
2. ... nowadays, when there is no Beis-Hamikdash - he must let it rot.
(c) He cannot redeem the fruit with money - because one Tahor fruit purchased with Ma'aser Sheni money cannot be redeemed outside Yerushalayim.

12)
If someone purchases an animal with Ma'aser Sheni money ...
1. ... outside Yerushalayim be'Shogeg - the sale is invalid.
2. ... be'Meizid when the Beis-Hamikdash is standing - he must take it to Yerushalayim and eat in in Yerushalayim (see Tiferes Yisrael).
3. ... nowadays, when there is no Beis-Hamikdash - he must kill it and bury it together with its skin.

13)
(a) The Mishnah prohibits using Ma'aser Sheni money to purchase Avadim, Shefachos, Karka'os and Behemah Temei'ah - because, since they are not food, they are precluded from the 'K'lal u'P'rat u'Ch'lal'.
(b) If one nevertheless did - he must eat fruit to the value of what he purchased in Yerushalayim (see Tos. Yom-Tov).
(c) The Tana does not simply declare the sale invalid (like it did in Mishnah 5) - because he is speaking either when the seller is has disappeared or be'Meizid.

14)
(a) The Tana forbids using Ma'aser Sheni money to purchase Kinei Zavin ve'Kinei Yoldos, Chata'os and Ashamos. Kinei Zavin ve'Kinei Yoldos comprise - a pair of pigeons or young doves.
(b) The Tana forbids it - because an obligatory Korban can only be purchased with Chulin money.
(c) It goes without saying - that one cannot purchase Olos with Ma'aser Sheni money, since they are not eaten (Tiferes Yisrael).