You can bid for postcard-sized works by famous artists at this secret auction

Think you can identify the work of a great artist at a glance? Time to put your money where your mouth is 

How do you collect valuable art in London? In the same way most of us manage to live in this city  – downsize. At the Art on a Postcard auction, there’s a chance to bid on itty-bitty works by famous contemporary artists at a starting price of £50, but as with most things in life, there’s a catch. You won’t know who has made what until after the bidding has closed. You could be placing the contents of your tax rebate against an original Maggi Hambling, or the work of an unknown Central Saint Martins student. Either way, you’re doing a good thing – all proceeds will go to the Hepatitis C Trust.

There are some big names on the line-up, not least the performance artist Marina Abramović, whose output is not something you can normally buy off a shelf – it’s hard to put a price on staring into the eyes of thousands of strangers. Who knows, maybe Marina has found a way to transcend physics and distil herself into the 10cmx15cm card? Among others who’ve contributed work are (deep breath) Helen Beard, Boo Saville, Rebecca Salter and lots more with ‘RA’ after their names: it’s like a Polly Pocket Summer Exhibition.

If you don’t have a knack for discerning artistic styles there are other ways to crack the code (the online auction opened on October 30, and some works have already acquired suspiciously high bids). Sadly there will be no auctioneer’s chant or slamming hammers at the exhibition venue – the whole auction takes place online (closing on Thursday), but you can visit the works in person to find out just how well you know your art. There are 417 postcards to choose from – a smorgasbord of paintings, drawings and prints – and it’s up to you to find the big cheese. Find the exhibition at WeWork, 8 Devonshire Square, EC2M 4PL. Tube: Liverpool St. Exhibition Tue Nov 13-Fri Nov 16. Free. Auction closes Thu Nov 15, bid online here.   

Art Editor's pick

‘Hyper-colour snogging, a psychedelic rainbow of tongues-out passion – this little beauty is everything you want a make-out sesh to be. Who wouldn’t want to receive a postcard reminding them of the best kiss they’ve ever had?’ Eddy Frankel, Arts and Culture Editor

Find more art exhibitions in the city here

Check out this 85-metre long art installation at Southwark tube