Don't expect miracles. Most car dealers work on a margin of around eight per cent. Premium brands would have a little more wriggle room but the industry average is eight per cent so if you're going in looking for 10 per cent off, you're already asking more than the dealer can do. 

 

If you want a proper, chunky, TK Maxx discount, go in and buy a car that's been registered as a demo, usually on the last day of the month. It'll still be delivery miles only and you'll get a hefty chunk off the price.