When most consumers buy items, they aren’t usually thinking about whether the prices of those items will depreciate or increase; they are thinking about how they will use or enjoy what they have bought.

Some buyers, however, aren't just consumers: they are investors. These are the keen-eyed, the thinkers-ahead, the people who try to predict how the market for an item or commodity will evolve over time. The range of things that people buy speculatively is vast - and often surprising.

We’ve uncovered some of the biggest returns that people have seen on various investments over the years and some of the price increases may shock you. Our interactive graph reveals some of the quirky items you would have been wise to purchase over the last few decades, and how much you could have made!

Back in the day, many of these items would have been bought without thought for their future value and, while It’s well known that private number plates have excellent investment potential, some of the other items may come as a surprise.

If you had been lucky enough to purchase the private registration ’RO11 LER’ just eight years ago for £448, then you would have profited by £17,052. Similarly, if you had paid £513 back in 2014 for the registration number ‘TAH 32A’ you would have made £16,987 - with a return on investment of 3,314%.

Here are our top 10 items that have shown the greatest return on investment: (NB: In this table, and in the interactive graphic, anything over £100/$100 has been rounded to the nearest pound/dollar.)

Item Year Value at purchase Value at last sale Return on Investment
The Roses error stamp 1978 £0.77 £130,000 16,883,017 %
Silver 2p 2015 £0.02 £1,400 6,999,900 %
Domain eBet.com 1996 £124 £1,026,135 826,562 %
God Save the Queen by the Sex Pistols (single) 1977 £4.80 £16,450 342,608 %
Harry Potter and the Philosopher's Stone first edition 1997 £19.63 £60,186 306,502 %
Batman Adventures (comic) 1993 £1.68 £608 36,095 %
Charizard Pokemon Card 1999 £5.03 £1,000 19,781 %
50-year-old Macallan Whisky 1985 £122 £19,003 15,414 %
Number plate: RO11 LER 2010 £448 £17,500 3,802 %
Number plate: TAH 32A 2014 £513 £17,500 3,314 %

Take a look at what people are investing in today - the next tech gadget, popular books, bitcoin? Predicting the items that will give the biggest return on investment could make you a lot of money in the near future. Oh, and don't forget to check your attic for the things on our list!

View our interactive comparison.