I suppose: 1) You'd like to write as below: 現金収入が少ないため、費用をかけずに行わなければならないか**ら**である。 　　"ならないかなである" doesn't make sense as well "ならないかな、である", as for me. 2) This sentence is telling the reason or explanation for something written before it. 3) We cannot see what they are doing, or are going to do, in the given sentence. So I would say: Because we have to carry it out at very little expense for lack of (enough) cash income, 現金収入が少ないため=不十分なため： for lack of (enough) cash income 費用をかけずに＝少ない費用で：at very little expense 行わなければならない：we / they have to carry it out / carry it on からである： Because

It seems to me a more natural way to write the sentence is as follows: 現金収入が少ないため、費用をかけずに行わなければならないかな、である。 The translation would be: "It has come to be that, given the low cash income, we must carry on without incurring expenses." or "It has come to be that we must carry it out without incurring expenses, given the low cash income."