The annual Chasewater Transport Show has fast become a popular event on the regional calendar, attracting more than 6,000 visitors. Last year it almost doubled previous visitor records with 10,000 people attending.
But the sponsorship blow has left organisers short of at least £1,000 and they said they cannot even afford the price of stamps to send out 450 entry forms.
Around 500 classic, vintage and modern vehicles take part in the show at the Chasewater Country Park with trophies in nine classes.
The event costs £6,500 to put on, including £500 for public liability insurance and payments for the hire of the site, including car parking facilities, generators and portable toilets.
The packed programme of entertainment, which traditionally features stunt teams, funfair, simulator rides and musicians, adds at least £2,000 to the total bill.
Cannock-based Helen Borton, aged 28, who launched the show five years ago, said she was concerned that she could not even start organising the event in April because there was no money in the bank.
"I've really hit rock bottom and I'm worried whether this year's show can go ahead. By this point I have normally sent out the entry forms but at the moment I haven't got the £180 it will cost for the second-class stamps.
"If someone doesn't come forward soon, I've got a lot of people to disappoint."
The continuing economic gloom is blamed for the withdrawal of two sponsors. Miss Borton, of Walnut Drive, said companies were promised a great deal of exposure with banner space, logos on the 5,000 flyers and all printed material, and trade space at the site.
Norton and District Funeral Directors and Need 2 Insure car insurance have remained as sponsors.
The event last year raised around £1,000 for the Help for Heroes charity. Anyone willing to sponsor it is asked to call 07769 288708.