This tells me only of (one who has) much (tithes). Whence do I derive (the same for one who has) few (tithes)? From "so that you cannot carry it" (which can be understood as "so that you cannot carry it such a long distance").
This tells me only of a poor man (who lacks animals and wagons for transportation). Whence do I derive the same (i.e., "then you shall change it to money") for a rich man? From "for the L-rd your G-d will bless you."
(Ibid. 25) "then you shall change it to money": This tells me that he can exchange it only for silver ("Money," literally, is "silver.") Whence do I derive that he can use other coins as well as silver? It follows, viz.: Since offerings may be redeemed for silver and second-tithe may be redeemed for silver, then just as offerings may be redeemed for other coinage as well as for silver, so, second-tithe may be redeemed for other coinage as well as for silver. — (No,) this may be true of offerings, where other movables are equated with silver — as opposed to tithe, where other movables are not equated with silver! It is, therefore, written (twice, in 14:25) "money," "money," to include (any kind of money). (Ibid.) "vetzarta the money": Something which is customarily bound (litzror). These are the words of R. Yishmael. R. Akiva says: something which has a design (tzurah), to exclude an asimon (uncoined metal), which has no design.