42. If there are limits on the amount a candidate can spend, what is the limit?

Source: 

Section 3, Regulation of Election Expenditure Act No. 3 of 2023

3. (1) Within a period of five days after the conclusion of the period of nomination specified in the Proclamation or Order requiring the conduct of an election under any law specified in section 2, the Election Commission shall, in consultation with the recognized political parties, and the independent groups contesting such election, fix by Order
published in the Gazette, a sum of money in Sri Lankan rupees to be used for the purpose of calculating an authorized amount, in accordance with the provisions of this section, for such election:
Provided however, in the case of a presidential election, every candidate who has not been nominated by a political party shall be consulted.

(2) Such sum of money to be fixed under subsection (1) shall be calculated taking into consideration the prevailing inflation rate and the National Consumer Price Index of Sri Lanka.
(3) The authorized amount in relation to a candidate shall be calculated as follows:-
(a) in the case of an election conducted under the Local Authorities Elections Ordinance (Chapter 262), the amount in Sri Lankan rupees resulting from the multiplication of the total number of registered
voters in the ward of the local authority contested by the candidate, by such amount of Sri Lankan rupees as may be fixed for that election by the
Election Commission under subsection (1);
(b) in the case of an election conducted under the Provincial Councils Elections Act, No. 2 of 1988, the amount in Sri Lankan rupees resulting from the multiplication of the total number of registered voters in the administrative district contested by the candidate, by such amount of Sri Lankan rupees as may be fixed for that election by the Election
Commission under subsection (1);
(c) in the case of an election conducted under the Parliamentary Elections Act, No. 1 of 1981, the amount in Sri Lankan rupees resulting from the multiplication of the total number of registered voters in the electoral district contested by the candidate, by such amount of Sri Lankan rupees as may be fixed for that election by the Election Commission under subsection (1);
(d) in the case of an election conducted under the Presidential Elections Act, No. 15 of 1981, the amount in Sri Lankan rupees resulting from the
multiplication of the total number of registered voters in the electoral districts in the Island, by such amount of Sri Lankan rupees as may be fixed for that election by the Election Commission under subsection (1).

https://www.parliament.lk/uploads/acts/gbills/english/6287.pdf 

This amount is not a fixed amount. The Election Commission of Sri Lanka collaborates with political parties to decide a per-voter rate, which needs to be done within  five days after the conclusion of the period of nomination. The calculation of the authorised amount for candidates depends on the election type:
Local authority election:
Limit = number of registered voters in the ward ×  per-voter rate
Provincial council election:
Limit = number of registered voters in the administrative district × per-voter rate
Parliamentary election:
Limit = number of registered voters in the electoral district × per-voter rate
Presidential election:
Limit = total number of registered voters in Sri Lanka × per-voter rate