TV channel Five has said it will be the first UK broadcaster to offer parts of its shows for sale as legal downloads.
Fans will be able to buy clips of 12 car reviews over the internet
From Monday, viewers of motoring show Fifth Gear can pay £1.50 for "DVD quality" downloads of car reviews.
Legal music download sites have become hugely popular - but TV companies have so far not used the same technology to put programmes online.
But British viewers illegally download US shows in relatively high numbers, recent research suggested.
Producers said reviews of 12 cars such as the Porsche 911 and Ferrari F430 would be available to buy as downloads from Monday.
Fifth Gear's "shoot-outs", where similar cars are raced, would also be available, they said.
Download company 7 Digital, which is providing the technology for the online shop, said TV companies were increasingly keen to earn money from the internet.
Managing director Ben Drury said: "Broadcasters have seen the revenues attainable from music downloads and are eager to do the same with their own content.
"TV footage can work so much harder for broadcasters, with the internet now a commercially sound distribution channel."
Fifth Gear executive producer Richard Pearson added: "Ever since Fifth Gear launched in 2002, viewers have regularly asked whether it's possible to purchase content. It's great that we can expand the Fifth Gear brand in this way."
In a recent report by web tracking company Envisional, UK viewers accounted for 18% of global illegal downloads of US hits such as 24, Desperate Housewives and Six Feet Under.
A typical episode of 24 was downloaded by about 100,000 people globally, the report said, with an estimated 20,000 of those coming from the UK.
The BBC has already run trials with what it calls its Interactive Media Player (iMP), which lets users download programmes for free for up to eight days after they are on TV.