There are limits on the amount a party can spend - both in relation to elections and to its on-going activity.
"...A party group or a new party group shall not make election expenses in an amount exceeding seventy financing units."
Source: Article 7(b), Parties Financing Law, 1973.
A party group shal not,l for one year, make on-going expenses in an amount exceeding 160% of the amount it entitled to for the financing of its on-going expenses... or in an amount exceeding 160% of the amount that a party group with five members of the Knesset is entitled to, whichever is greater."
Source: Article 7(d), Parties Financing Law, 1973.