It's the Bunnings slogan everyone's heard - a promise to beat a competitor's price on the same stocked item by 10 per cent.

But there's a catch to the hardware giant's famous price guarantee.

While Coles and Woolworths have been under intense scrutiny, Bunnings - which has a much higher profit margin than either of them - has mostly escaped attention.

In-store, a 0.9m Citeco ladder sits behind a large red sign with the same commitment: Find a competitor with the same in-stock item - 10 per cent off.

But there is no competitor that stocks the Citeco 0.9m ladder.

That's because Citeco is a Bunnings home brand. Not only is it manufactured for Bunnings, the hardware giant also owns the Citeco trademark.

It's far from the only item.

Through the trademark register and questions to Bunnings, Four Corners has found the hardware giant has more than 9000 home-brand products.

If you can find these Bunnings buckets cheaper elsewhere, Bunnings says it will beat the price.