A new internet car shopping service is posing a fresh threat to established websites like Autobytel and Autohit, which charge dealers monthly subscription fees.

Dealers using Ybag pay for leads generated up to a maximum of £120 a month. Any leads received after this limit are free of charge.

Currie Motors, Alan Day, Dixon Motors, Perrys and 25 smaller dealer groups have already signed up. The number is expected to rise to 250 by late February when the site www.ybag.com begins operations. In the first three months there are no fees to pay.

Ybag intends to spend £2.5m on ads and promotions in the first seven months attracting consumers and dealers - the service will only be available in the UK.

Consumers will be encouraged to set up private 'Ybag mailboxes' where they can make requests by typing in text such as: 'I'm looking for a black BMW 3 Series with less than 10,000 miles. I'm prepared to travel 50 miles.' They will also be able to enter requests for servicing, repairs and accessories.

Dealers, who see the first section of the postcode, but not the identity of the prospective purchaser, are obliged to make a sales offer within 24 hours. They are allowed to attach sales messages and provide a link to their website from which they can make on-line sales.

Dylan Schlosberg, founder and CEO of Ybag, said: “Unlike other consumer driven automotive e-commerce services that provide dealers with purchasing requests, we are more cost effective because we are a comprehensive shopping site which offers a service to both buyers and sellers and as such make the majority of our revenue through third party advertising."