I'm confident the charity shop 'volunteers' make good scratch off of having first pickings on everything that comes in.
It kind of is. Not in that way though. Flea-markets aren't really a thing in England at least by name. So this was probably a jumble sale or a car boot sale.
A jumble sale is a small indoor ad hoc second hand market probably not on any very regular schedule. They're usually run by small groups (church congregations, scouts, womens' institute) for fundraising and social purposes with the items donated and all the proceeds going to the group.
A car boot sale is held in a parking lot or field, where the sellers pay for the pitch and the buyers sometimes pay to enter. As the name suggests, many of the pitches will just be sellers with a car full of junk. They may be run commercially or by groups with access to suitable grounds (e.g. a rugby club). They're more work and staff to organise so they're often on a regular schedule (e.g. first Saturday of the month).
I love flea-markets of all types :)
In America we also have car boot sales, although “jumble sales” are called rummage sales here.
And yeah, whatever ya call them it’s always fun exploring and buying other people’s stuff. I especially love crystal glass bowls and jars. That and other shiny things bring out the corvid in me.
Incidentally I now live in Sweden where Loppis (literally "flea") markets are common and delightful. Some are all year around affairs while others just pop up at the weekends in the countryside summer months as the population sweeps out of the cities for their summer vacations. I love poking around through other peoples' crap!
One last thought - my family used to swing by an antiques auction in Tring in Hertfordshire (the county this cannon was discovered in). Over the years a variety of bits and pieces were acquired there - some rather nice. After my parents died they did the house clearance for us. Dust to dust...
Sound like good targets, though.
You fight with what you have which isn't always a stockpile of cannon balls.
When cannonballs hit ships splinters often provided area of effect carnage. However, on an open field a cannonball would only harm a few people and could simply miss.
The Yu-Gi-Oh! cards, however, were the extremely fun poorly translated ones. “Spell Slame”, “GGGG”, “Rock Corrosion Devil - Love Fake”. I think my favorite though was a “Storm King” I traded for a legit Blue-Eyes Ultimate Dragon. I told the kid like 3 times it was fake, but he was bound and determined. Worked out for me, since I ran Blue-Eyes, but was just very weird.