In some weeks, Auckland cleaner Po'oi Kei has a bit of money left over to put away after paying the bills and buying groceries.
In other weeks, there's not even enough money to pay the bills.
Tongan-born Mr Kei, 34, his wife Seini, 27, and four children aged 1 to 9 are exactly the kind of marginal savers whom KiwiSaver is designed to help.
He is the family's sole income earner, cleaning Qantas House in Queen St from 5am to 10am for $11.30 an hour, and then another office in Newmarket from 6pm to 11pm.
Mrs Kei often helps him in the evening job so he can finish in time to get a decent sleep before getting up for his 5am start the next day, but she is unpaid.
His total gross income of $570.75 a week means he would have to save $22.83 a week to reach the 4 per cent threshold for KiwiSaver.
Interviewed through an interpreter yesterday before the Budget, he initially said he couldn't do it.
"There's no money in the bank. He can't save any money because of the low wages he is living on," the interpreter said.
"He's spending money on the children and the bills - clothes, shopping, school uniforms and nappies."
The family pay $80 a week in rent for a Housing New Zealand house in Hillsborough. After taxes and rent, even allowing for the family tax credit (formerly family support), Mr Kei said the family had only about $360 a week to live on.
After the Budget, it was hard to explain to him that if he could save $22.83 a week, the Government would give him back $20 a week, but only when he turns 65.
With nothing to help the family's immediate cashflow, all he could do was to repeat that sometimes he simply did not have enough money.
This may, however, be only because he is not getting the family support he is entitled to. By Herald calculations, the family are entitled to $328 a week in family tax credit and in-work tax credit on top of a net income of $454, giving it a total net income even after rent of $702 a week - perhaps enough to save.
At the other end of the income scale on a joint income of $95,000 a year ($1827 a week), Chris and Gaby Munro of Sunnynook on the North Shore reckoned that they would now join KiwiSaver, despite the cost for them of $73 a week.
"It would be tight, but I think we'd like to do it," Mr Munro said last night.
But he said even a $5000 or $10,000 Government gift towards a house deposit after five years would not be enough to make buying affordable. They currently rent at $350 a week but would need to pay $672 a week on a $336,000 mortgage.
"I think the KiwiSaver is a good idea. People need incentives to save," he said.
"But I don't think a $20 a week tax credit is enough. I think he [Dr Cullen] could have offered more."