The 'BringRonaldoHome' movement, started by friends in Australia, aims to collect £10 contributions from 10 million Manchester United fans to put towards a £100m offer for the Portugal international. The Real Madrid star reportedly has a £100m release clause.
The group have created a 'crowd-sourcing' platform where United supporters can help raise money by spreading the word on social networks like Facebook and Twitter to their friends.
The movement was started three days ago and the report claims it's already received thousands of pledges to donate. According to www.BringRonaldoHome.org, more than 3500 United fans have pledged so far.
A spokesman for www.BringRonaldohome.org told the Daily Mail: "We have been inspired by the loyalty and dedication of United fans.
"To be a 'true' fan requires the 'living' experience of football. It is not about being a mere spectator, it is about being a participant.
"We wanted to give fans an opportunity to be involved.
"The internet is now a significant resource in the world of football. Fans spend increasing amounts of their time on football web sites accessing up-to-the-minute information about events specific to their team and discussing issues on blogs.
"What we have done is develop a construct, based on crowd funding principles, which will tap into this incredible global fan support that Manchester United has - to help deliver the goods - to give the fans an opportunity for their voice to deliver an action."
The website claims the money collected will be provisionally passed on to Manchester United - who will then be able to use the cash to clinch Ronaldo's transfer from the Bernabeu.
If they fail to reach their target, the £10 donation will be returned to the pledger. But if they're successful they've promised to send each donator a Ronaldo Manchester United shirt.