20. Is there a limit on the amount a candidate can contribute to their own election campaign?

Source: § 5 and § 6, Law No. 181 on the election campaign and amendments to Law No. 85 on political parties and movements, 2014 (amended 2019)

Candidates can receive private donations without limit from legal entities, political parties and individuals until 48 hours before election day.
Source: OSCE/ODIHR (2019) Slovak Republic, Presidential Election, 16 March 2019. OSCE/ODIHR Needs Assessment Mission Report. OSCE/ODIHR, Warsaw

There are no explicit limit on the amount a candidates can contribute to their own election campaign.