R. Elijah Schochet, Bach, Rabbi Joel Sirkes: His Life, Works and Times (expanded edition), p. 29:
There were some who undoubtedly begrudged Sirkes his wealth. One outspoken critic, due to personal religious convictions, was Rabbi Eliezer Ashkenazi, author of Damesek Eliezer, who accused Rabbi Sirkes of violating an accepted practice of Jewish tradition by accepting money for the performance of rabbinic services. Sirkes, himself, agreed that no rabbi should, ideally, derive material benefit from the study of Torah. However, he maintained, owing to the vast field of Rabbinic Literature extant, it had become virtually impossible for one to earn a livelihood and also become a competent scholar at the same time. Only financial gifts from generous donors could enable a rabbi to devote all of his energies, with peace of mind, to the mastery of Jewish Law.Note that this book is currently available in stores. I saw that Judaica Place on Avenue M in Flatbush has the book in stock.
Sirkes was of the opinion that wealth served an additional function as well; that of enhancing the authority and influence of the possessor. He lamented the lack of respect shown by the masses toward a poverty-stricken scholar and argued that the possession of wealth is an indispensable prerequisite for a rabbi.A Rosh Yeshibah, who is equivalent to a High Priest or to a king, needs to be wealthy, in order that his teachings should be re-spected. It is permissible for such a one to accept gifts, in order that he may grow to become wealthy.Apparently most concurred with Sirkes’ views, for by the end of the seventeenth century, paid services were an accepted part of rabbinical remuneration. Rabbi Nathan Hanover of Zaslav, a contemporary chronicler, summarizes the prevalent norm in his Yeven Metzula:… each and every community would support Yeshiboth, and give generous remuneration to its head, that he could maintain the Yeshibah without economic concern for his own welfare.As for himself, Sirkes was fortunate in being able to follow his own advice; he achieved great financial status with which to further enhance the authority of his teachings.
 Chapter Elu Terefot, no. 7. Ashkenazi forbids any direct financial gain from the study of Torah. He cites the example of Rabbi Judah Loew of Prague, who derived permissible financial income as a marriage broker. He suggests that many indirect sources of income, such as a fixed fee for solemnizing marriages, could adequately provide for most needs of a rabbi. Ashkenazic rabbis had long been criticized for accepting fees for the performance of religious services. Rabbi Obadiah of Bertinoro takes them to task for such offences, declaring: “If one accepts payment for deciding a legal case, his decision is null and void.” (Mishna, Berakhot, 4:6. See also Ketubot, 105a.) Maimonides, too, declared his opposition to rabbis receiving remuneration for adjudication. (Commentary to Ethics of the Fathers, Chapter 4.) Indeed, from a responsum of Israel Isserlein (Pesakim uKethabim, no. 128), it would seem that some rabbis derived their entire income from fees for their religious services. Joseph Karo permitted only the acceptance of fees for שכר בטלה, compensation for interrupted labor, Beth Joseph, Eben HaEzer, 130, while Isserles, ibid., felt a rabbi to be entitled to a regular remuneration as well.
Zimmerls, Ashkenazim and Sephardim, 271, speculates as to the existence of a moral motive behind the fixing of a steep fee for a writ of divorce; namely to discourage divorce. But this would hardly explain the fee for the performance of weddings!
See I. Heilprin, Beth Yisrael BePolin, 73, for further comment on income derived by rabbis from the performance of weddings.
 Responsa BH, no. 52: Sirkes defends his views. The problem is more fully discussed in BH, Yoreh Deah, 246:15.
 Responsa BH, no. 52: Sirkes occasionally refers to his views on the subject in Meshib Nefesh, his commentary on the Book of Ruth. זוכה להון ולעושר כמשמע שעל ידי כך דבריו נשמעים. Elsewhere he refers to a man’s having rabbinic scholars for sons-in-law as a just reward for his having given generously of his wealth to rabbis.
 S. Baron, The Jewish Community, Vol. 2, p. 85.