RR Auctions is the only auction house I know that does computers
Then there are vintage computer festivals all over the country now and they have sales and markets. Find one close to you and sell it there.
This thread may push me to try again.
If it's not very obscure just sell at the prices they go for on ebay; would strongly suggest selling as "for parts" and clarify they're not fully tested because it's wild how often ebay buyers seem to encounter issues with used items and require a partial refund (they rarely want to return the item). The cut on selling price by listing for parts will not be that significant most of the time with older tech in my experience.
If it is quite obscure you'll probably have to accept that it might be a long time before you even get an offer and the price can be incredibly hard to pin down. I've bought things for close to zero that I've also seen go for hundreds just because someone wanted rid of them, I've had offers around 25% of the listed price being accepted but I suspect those same listings were skipped over by people who would've paid more. Prices can vary dramatically depending on whether the few people who might want a thing are actively looking for it.
The old ones won’t have internet capabilities and were mostly for business settings, so do you just fire up Lotus123 and click around in a spreadsheet?
Or do they just look cool on a shelf?
I had success selling a maxed out Power Mac 6100 there that went nowhere on EBay.
Does the condition of your goods match that market segment's expectations?
Does the combination of your sunk cost and margin expectations allow you to sell at an attractive price in your target market segment?
What is your sales timeline?
How much effort do you want to put in?
Good luck.
Honestly, you’ll probably be disappointed by how much time it takes and how little money your junk is worth.
Just throw it away.
Or insist it has value and let your family deal with it after you die. That’s my dads plan.
Prepping for sale can help. There seems to be a category of buyers who not only want something clean, but that's had the original software restored, or something like that. For "vintage" PCs, this means putting on a vintage version of Windows, maybe not the one that came with it, but XP or something that people really liked and will run old software they have. For non-PCs, like 8-bits, I'm just guessing there are also buyers who want a good out-of-box experience, to play with for nostalgia, without having it be a restoration project for them.
Also, specs do help for even "vintage" PCs, even ones that don't matter much, and aren't collectible. The larger the SSD you retrofit into it, it seems the more people are willing to pay, like someone is thinking of a Windows XP box as a daily driver for a video collection in 2024. Maybe people just like the idea of a Windows XP dream computer, and big specs help. People also seem to pay more for very minor CPU boost, even if the only difference is a 10% clock rate difference, same cache, and even if the CPU is socketed and they could upgrade it themselves. (It's easier to understand people wanting, say, the slightly faster variant of an 8-bit.)
Condition and cleanliness also helps. Keyboards tend to show wear and accumulate grime you'll never fully get clean, and a $20 replacement keyboard, combined with wiping down the chassis with isopropyl 70% prep pads, can elevate condition of a laptop from gross to great. Older desktop keyboards, you can disassemble them to clean, and this works surprisingly well for some of them, so you're pretty much only cleaning big plastic parts under the faucet.
But -- I implore you -- don't spray an eBay item with Febreeze or a scented duster. In the last couple years, most of the electronics I buy on eBay have had this done to them. Like, there must've been a TikTok, or something, that told people this was a best practice. The VOCs are nasty, and can persist on/in the item for weeks or longer.