Five boards in the Birmingham area were offered for free
Giant hoardings have gone up in the Birmingham area to help the campaign to keep the Staffordshire Hoard in the West Midlands.
The Art Fund's campaign has until 17 April to raise the £3.3m needed to buy the hoard of Anglo-Saxon gold and keep it in the region.
More than £500,000 has come in through donations in two weeks.
A company managing sales space on boards, Signature Outdoor, offered five of them for free.
The five boards, including two by the M6 motorway, would have cost £65,000 in total over two weeks.
Almost 1,500 Anglo-Saxon artefacts were found in a field near Lichfield by metal detecting enthusiast Terry Herbert last July.
More than 80 artefacts from the hoard will go on show at Stoke-on-Trent's Potteries Museum and Art Gallery next month.
The campaign was launched on 13 January by celebrity historian Dr David Starkey.
The Art Fund said it feared the collection could otherwise be bought by private collectors and split up.
Staffordshire Hoard fundraising manager Holly Smith-Charles said: "We had a group of schoolchildren who'd been studying Anglo-Saxon history with their primary teacher.
"So they all rallied together and made a donation as a whole class, which was great."