It never ceases to amaze me how what are, frankly, in my opinion a series of unattractive daubs flung together in the name of Contemporary art can make millions at auction when highly accomplished and rather beautiful Victorian landscapes can be had for buttons.

A recent trip to see the excellent Courtauld exhibition, Seurat and the Sea, was a useful reminder that back in the 1880s, they were also breaking new ground in art. Seurat, with Pointillism, or Neo-Impressionism as it was also called, was miles ahead of his time in showing how blending complementary but opposite colours on the spectrum could create all the light, shade, depth and life a painting needed. He died at just 31, having completed no more than 45 major paintings – all of them a treat for the eye on any wall.

I suppose that fashions change and, with them, tastes. Don’t get me wrong, I think a great deal of Modern and Contemporary art has a lot to offer, but it is also rife with mountebanks. However, despite the marvels of Seurat and the leading lights of late 19th century art, the flipside of what has been a rather subdued market for late Victorian and Edwardian painting is that you can pick up stunning art for very little indeed.

Just browsing through one of the online auction platforms the other day, I worked out that, with a fair wind behind me, I could fill a whole wall with stunning Victorian and Edwardian watercolours for less than £2000. Some of the pictures looked a bit tired, but closer inspection revealed that they simply needed a new mount and frame, and at these prices this was very much a realistic option.

I have no idea whether art like this will enjoy a renaissance in years to come – although it certainly deserves to – but those cherry picking now will be in the best position to capitalise if it does. And if prices remain in the doldrums, well they will have a fantastic selection of art gracing their walls, which they will never tire of.

Getting the asking price right is as much a skill at chattels auctions as it is when putting your home on the market: price it too high and you can kill demand, but undercook it and you risk giving it away.

Overexposure over a prolonged period tends to raise questions as to the condition of the property on offer. A newly redeveloped house near me has recently gone on the market for around 30 per cent more than I would think is reasonable. This is because it will have been priced according to what the plot cost to buy, what the developer paid to knock it down and create the house that now stands there, and what their projected profit is added on top. No one has shown any interest. After a while, market reality will kick in and it will be re-priced accordingly, but that exposure will cost the owner dear and they may well end up with less than if they had simply pitched it at a more competitive rate in the first place.

It’s the same for chattels auctions. Those prepared to consign items at come-and-get-me estimates very often spark a bidding battle, with lots selling for what they really hoped to get for them, or even higher.

Likewise, dealers exhibiting at fairs will often start to discount pieces if fail to shift after a day or two – better to sell something a for a bit less than return home with nothing to show for all the time and expense spent.

Oddly, if you cross the Channel, you will find that French dealers exhibiting at fairs will take the opposite approach. If little or nothing sells, they will start to put prices up, arguing that they need to make up the shortfall. It doesn’t seem to occur to them that potential buyers are even less likely to stump up the cash if what they are looking at is more expensive. It’s a cultural difference, I suppose, but I can’t believe that the French way is a successful strategy.

When something is aesthetically appealing, beautifully made or intrinsically valuable, it is easy to see why bidders will compete for it at auction.

Rarities, too, command attention, and for the rarest even poor condition can be no barrier to an impressive hammer price.

But some people like oddities, even the macabre, and I have come across quite a few in my long career at the rostrum.

Take, for example, The New Patent Exploding Trench. A WW1 toy produced briefly by Britains, it involved a wooden and fabric trench loaded with six lead riflemen of the Gloucestershire Regiment. When hit, a specially placed flagstaff set off a cap, which made a loud report, shaking the trench and “killing” the soldiers. Why a British factory should have put British soldiers rather than the enemy in the trench is anyone’s guess, but it was a marketing disaster as a result and the toy was soon withdrawn. The result? A rare collectable that has made a decent four-figure sum in the three or four times it has appeared at auction over the past 30 years.

Perhaps the most chilling thing I have seen was not at auction but at a restoration firm. What looked like a framed piece of parchment turned out to be a collection of tattoos cut from the bodies of French soldiers in the field of Waterloo. Now who would want to buy that?

Perhaps the most disturbing item I have come across is a Fiji Mermaid. This has its origins among Japanese fishermen, who sewed parts of different animals together to create chimera – in this case the head and arms of a monkey sewn to the body and tail of a fish.

They first came to Western notice after the captain of an American ship, thinking it a real creature, bought one from Japanese sailors in the early 19^th century for thousands of dollars. The great American showman PT Barnum displayed it as a curiosity in the 1840s.

As a trip to Wikipedia will attest, Barnum understood how to generate publicity, writing to the newspapers under various pseudonyms on the subject of the Fiji Mermaid and creating a ruse whereby his associate booked into a Philadelphia hotel, secretly showing the creature to the manager, who then insisted on spreading the word and staging a display to a select audience, including journalists.

Probably destroyed in a fire around 20 years later, by then the legend had caught on and many copies were made. Look it up on Google images and see one for yourself.

Each example is usually named after the town in whose museum it now rests.

For all you romantics out there, the impending excitement of Valentine’s Day is doubtless at the front of your minds right now. But you should also know that it is an exciting theme for collectors, because vintage Valentine cards have all the attributes required for attracting them, and some can sell for hundreds of pounds.

Legend has it that the first Valentine message was sent in the 15th century, but the first cards arrived with the dawn of the modern postal service in the first half of the 19th century. The earliest known printed Valentine’s card dates to 1797 and was published on January 12 that year by John Fairburn of 146 Minories, London. It depicted a young woman in a landscape setting at the centre, surrounded by cupids, flowers, birds and other symbols of love, as well as messages. In 2013, that made a creditable £450 at auction.

Elaborate cards decorated with lace and ribbons – and even some with moving parts – demanded a considerable outlay on the part of the purchaser. Most popular were the ‘marionette’ cards, with their paper dolls with moving limbs, created by Raphael Tuck, who worked under Royal Warrant.

Celebrated artists and illustrators of the day were drafted in to create designs which collectors seek out now, among them children’s author Kate Greenaway.

The Museum of London has a collection of more than 1700 Valentine’s cards.

It’s staggering to think that by mid Victorian times, the Valentine industry in Britain was so huge that it is thought the public spent hundreds of millions of pounds a year on cards and gifts for their loved ones. Today it is well over £1.5 billion in the UK.

The United States dwarfs that figure, generating almost $15 billion worth of retail sales each year. To put it in context, that is around a quarter to a third of the value of the entire global art market – auctions, dealer and gallery sales, fairs, private deals and so on.

Back in 2003, a Valentine card sent by Princess Diana sold for ten times its estimate at £2000, while in 2012 one sent by Amy Winehouse made £1600.