I visited the "Retro Computer Sale" which took place at the Centre for Computing History this Sunday (26-Feb-2023) in Cambridge. That's Cambridge, England BTW!
It's a small museum which has quite a number of exhibits relating to computer history in the UK. It is also "hands on" in that you can play games on a large range of home computers from the 1980's and consoles too. They hold events every now and again. Some years ago I attended a BBC Micro/Acorn Atom get together. Parking is limited. The museum is quite well hidden on a small industrial estate so it is easy to miss. Nevertheless Cambridge is a bit of a tourist hot spot in the UK, so if you are passing through you might want to plan a couple of hours for a visit. http://www.computinghistory.org.uk/. Entry was £10, the normal museum fee.
The area for sellers was quite small, but there was an impressive amount of retro stuff for sale, and prices were low. No Ebay prices here!
I was looking for old ISA cards and there were at least four sellers of old PC cards. More or less a quid each (I overpaid for the first 2 cards 😀 ).
I also bought an AOC brand CGA colour monitor for £50. What a bargain. They are really rare in the UK, don't appear often on Ebay, and when they do they are often damaged or not working, and cost a bomb. It works great !
Finally I bought a PC, again for £50. I didn't even look in the box. Came with an XT keyboard (DIN plug) which I really needed. I was alerted to what was in the unmarked box on the floor by a interested buyer, who only had £10 in cash on him. When he walked away I bought it. When I got it home I was surprised to see that it had a MFM hard disk, 384k plus I/O expansion card, original floppies and documentation (but was missing the MSDOS disk) and a VGA card. I discovered it was/is a Hyundai Super 16 8088. Interestingly the layout of my motherboard differs from those I have found online. HDD might be faulty. I have no 360k DOS boot disk. Interestingly the BIOS appears to be some hacked version to give compatibility with "CUB" monitors (a very well known brand of monitor used in UK schools in the 80's, usually with BBC micros).
I also got some other miscellaneous stuff: 2 mice; 8 old memory sticks; CF card to ISA adapters.
Other notable items seen: a Sharp MZ-80K in great condition (£120 at the start, reduced to £100 by lunchtime - what a steal? ) ; an Apple IIe in great condition for £100; a VT100 like terminal; seller of 3D printed joysticks/pads; UK101; PET; TI Color Computer; Atari 800, 400 and XL; plus other stuff I didn't even recognise. Ironically half of this stuff is already on display in the museum 😀
All in all, well worth the visit.