19. If there is a limit on the amount a donor can contribute to a candidate, what is the limit?

"Maximum value of donation at annual level that a natural person may give to political entities for regular work shall not exceed ten average monthly salaries. Maximum value of donation at annual level that a legal person may give to political entities for regular work shall not exceed 30 average monthly salaries. Donations exceeding at annual level one average monthly salary are published. A political entity is required to publish each donation referred in paragraph 3 of this article on its website within eight days from the date the value of donation has exceeded the amount of one monthly average salary." 
"A political entity may raise funds from private sources for election campaign expenditure. Natural and legal persons may give donations in a single calendar year in which elections are held, in addition to donations for regular work, also for election campaign expenditure up to maximum stipulated amount at annual level specified in article 10, paragraphs 1 and 2 hereof, regardless of the number of election campaigns in a calendar year. For financing election campaign expenditure a political entity may also use funds from credits and loans." 
Source: Articles 10. and 22. Law on financing political activities

10 average monthly salaries for natural persons, 30 average monthly salaries for legal persons, regardless of the number of election campaigns in a calendar year.