An extra pound;9.6 million of direct funding for Welsh schools was announced this week in a new-look "budget for children".
But the Conservatives accused Plaid Cymru of betrayal after it thrashed out a backroom deal with the minority Labour administration to get its pound;14 billion budget for 20078 approved.
The budget had been hanging on a knife-edge after opposition parties demanded more cash.
The new-look budget means that, for the first time in Wales, heads will receive special grants direct from government. These will range from pound;2,000 for the smallest primary to pound;16,200 for the largest secondary school, according to officials.
Janet Ryder, Plaid's shadow education spokeswoman, said her party had brokered a deal in the interests of Wales and schools.
"We are seeing a lot more than pound;9.6m here, in effect more than Pounds 13m," she said. "It means schools which have suffered from 1 per cent local government efficiency savings this year will have only 0.3 per cent taken out next year, and will also benefit from an extra dollop of cash on top."
Anna Brychan, director of the National Association of Head Teachers Cymru, said she was delighted with the new money, and the acknowledgement that efficiency savings had been passed on to schools as budget cuts.
But Nick Bourne, leader of the Welsh conservatives, said: "Labour's little helpers have sold out and betrayed Welsh pupils, parents, teachers and universities."