small note - finally saw a content creator who does something I've long thought this category of content creators should do (but most don't) - in this case he bought a collection of #mtg cards and made a video looking at what was in the collection (and estimating the value). He paid $400 - turns out the collection is likely worth about $2000 (at retail prices), he's likely to net about $1200 or so selling it via a "buylist" online.

So he is planning on sharing half the profits with the seller

there are a lot of content creators who film themselves thrifting or buying at garage sales or buying bulk collections of various items from various sources - and frequently going on about how great of a bargain / deal they found (frequently inflating the prices they may actually sell things at while emphasizing how cheaply they bought the collections/items.

Very Very few seem self aware enough of just how ethically grey this can seem - I've long thought that many should be seeking the sellers

I'm not unbiased here - I don't film it (perhaps I should) but I buy (small) collections of various items (most #mtg or #ttrpg older collecionts/lots) and while some go into my personal collections many go into my various online sales (eBay mostly but I sell via other places at times as well) Not huge amounts relatively speaking but it's something I have done for 30+ years off an on, mostly to fund my own collections and hobbies - but at times it was also how I paid my bills (most 30+ years ago)

and back then I did a lot of selling for other people - not everything I bought places to sell was my own collections - and I made a lot of money for folks (and was well paid myself - especially for when I was in my 20's, I could make my rent in less than 2 days at a good show, and cover all my monthly expenses with just a few more days - for being in my 20's it was a lot of fun

but the ethics of trying to find that seller who doesn't know what they have and getting a "steal" are questionable

I was far less concerned about the ethics of trading - in the past I typically traded roughly 2 to 1 - i.e. people typically traded me cards (in the case of mtg) worth about 2x the card(s) I had that they wanted. Typically only if I was fairly confident that I could trade/sell the cards they offered realistically (and/or if I wanted them for my own collections) but doing that consistently over time meant everyone was fairly happy - my inventory grew & people got the specific cards they wanted

but when folks talk about paying say $40 at a garage sale for items worth $1000's especially if they are further monetizing by making online videos about that buying/selling then I do think it is exploitative and gets really questionable.

(I'm less concerned about the folks buying say storage lockers etc where they also have to deal with everything in the space & that's real work (and can incur recyling/disposal fees etc)

So I really like hearing a creator saying he plans on sharing w/seller

reinforces also that someone whom I have watched and enjoyed watching their content because they seemed like a good person may, in fact, be what they appear to be (of course assuming they live up to their promises)