18. Is there a limit on the amount a donor can contribute to a candidate?

Electoral Act 1997.  Section 23A (inserted by section 49(d) of the Electoral (Amendment) Act of 2001) of the Act of 1997 is amended by substituting the following subsection for subsection (1): “(1) Without prejudice to subsection (2), none of the following persons, namely— (a) a member of either House of the Oireachtas, (b) a member of the European Parliament, (c) a candidate at a Dáil, Seanad or European election, (d) a political party, (e) a third party, or (f) an accounting unit, shall, directly or through any intermediary, accept from a particular person in a particular year— (i) a donation the value of which exceeds, in case the first-mentioned person falls within paragraph (a), (b), or (c), €1,000, (ii) a donation the value of which exceeds, in case the first-mentioned person falls within paragraph (d), (e), or (f), €2,500, or (iii) a donation of cash of an amount which exceeds €200."

There are limits.
Standards in Public Office Commission. 2017. Guidelines for Members of the Houses of the Oireachtas and Representatives in the European Parliament relating to acceptance, management and disclosure of donations, p. 15.