Sponsorship deals on the London Underground could help improve stations as well as freeze fares, Conservative politicians have said.
A report by the Conservative Party on the London Assembly said sponsors could contribute to station upgrades.
It also claims that Transport for London's (TfL) estimated cost of £4m to rename stations for deals was exaggerated.
TfL said it was open to sponsorship but the deals needed to be "appropriate".
TfL estimates the cost of renaming a zone 1 station for a sponsorship deal would cost almost £2m to change the name initially and then an additional £2m to change it back, which included changing posters, timetables, maps, bus and cycle guides. They argued the cost made a deal of that kind unfeasible.
However the report called, Sealing the Deal: TfL sponsorship feasibility study, said the cost of changing signs when Blackfriars tube was temporarily closed between 2009-2012 was only £8,500.
TfL says the changes at Blackfriars were not comparable as the name of station was not altered, but instead crossed out.
Gareth Bacon, author of the report and Conservative London Assembly Member, said: "TfL need to stop exaggerating their costs, which simply do not stack up.
"Instead, they should look to minimise costs wherever possible, for example by structuring contracts in such a way that these costs are part of the sponsorship deal."
Graeme Craig, TfL's director of commercial development, said it had secured £3.5bn in commercial revenue for coming years and had sponsorship deals already in place, such as the contract with Barclays for the capital's cycle hire scheme and Virgin Media's deal for wifi on the tube.
"We are, and always have been, open for business," he said.
"The mayor has always said that the sponsorship of Tube stations and other assets can happen if the sponsor is appropriate and the price right."
The report also said that sponsorship did not have to limited to renaming stations and suggested that companies could contribute to upgrades by adding mobile phone connectivity to platforms, installing TV screens in stations to broadcast news or even upgrading lifts and toilets in return for branding.
In a previous report the Tory politicians had claimed that if £136m was raised in sponsorship fares could be frozen for a year.
Fares on London transport increased by an average of 4.2% this year.