A pop-up shop has opened its doors, but this one is rather unique as it's selling stolen goods, legally we should add.

Back Me Up, an app-based insurance company offering customisable insurance, is behind the gimmick. It has scoured police auctions for covetable booty and made it all available to the public for a reduced price.

We went along for the launch of the shop in east London yesterday to find out what you can pick up.

What's for sale?

We found a Mulberry bag that would usually be £700 going for £250.

There was also a Macbook Air laptop usually £600 available for £400, a Jaeger trench coat usually £150 for £30 and even a harp worth £250 going for £45.

Back Me Up says the money raised from selling off this ‘Aladdin’s Cave’ of police seized loot will be donated to three charities: Mind, The Prince’s Trust and Shelter.

The pop-up event is open to the public from today until November 6 and you’ll find it at the Old Truman Brewery, 91 Brick Lane, London.

If you aren’t able to pop along there are other ways you can pick up a bargain by shopping lost or stolen goods.

Police auctions

Police sell off items that have been seized from criminals or handed in to police auctions and not retrieved by the rightful owner.

Typical items include jewellery, household items, and electrical equipment such as laptops and mobiles. Bikes, in particular, tend to go very cheaply.

Although some police forces hold live auctions – advertised by “seized assets” adverts in local papers – you can bid for items online too. Bumblebee Auctions sells off property seized or found by the police and works a bit like eBay.

If you win an auction, you’ll need to collect larger items from the police station in question or pay for postage of smaller items.

You can search for products, or by towns, and so only view items you’d be willing to go and pick up. To bid you need to set up a Bumblebee account and also an e-money account with Nochex, the only form of payment Bumblebee accepts.

[Read more: Poundland's new range costs a lot more than a pound]

Lost luggage auctions

Thousands of suitcases are mislaid by airlines each year and the ones that are never reunited with their rightful owners end up at lost luggage auctions.

British Airways flogs its lost luggage at auction house Greasbys in Tooting, south-west London.

Viewings take place every Monday afternoon to give you a chance to have a look at the bags you might want to buy, and auctions take place every Tuesday at 8.30am.

However, it’s all pot luck as you don’t get to see inside a bag or suitcase before you bid. Instead you have to guess at its contents. Chances are sports-style luggage is likely to contain sports clothes or equipment while top-of-the-range suitcases might contain some posh clobber.

Other auction rooms worth checking out BCVA in Bristol and Mulberry Bank in Glasgow. Another is Wellers in Milton Keynes, but this is closed until later in November 2016.

Bear in mind though that auctioneers will take very valuable items out of suitcases and sell them separately. So if you buy a suitcase hoping it will contain an iPad and £1,000 digital camera, you’re likely to end up disappointed. However, you can bid separately on valuables – and at least you’ll know what you’re getting, unlike the mystery suitcases.

If you decide to bid on suitcases bear in mind that as well as getting your hands on some decent clothes, books or toiletries, you’re just as likely to take home a bag of dirty washing.

After you’ve identified which suitcases or items you want to get your hands on, it’s time to bid at an auction.

The key to success is set a budget and stick to it – don’t get carried away. Suitcases tend to go from £5 to £50 so there’s a chance to make some decent cash – even if it’s full of junk, selling the suitcase itself could see you make a profit.

If you’re the highest bidder when the hammer falls, you’re legally obliged to pay for the goods.