In terms of the shiny Rayquaza (SL10) from the Call of Legends subset, in PSA 10 or 9.
I am looking into buying either of these cards in the near future, but struggle to find accurate, recent prices online, e.g on eBay. Does anyone have an idea of what I could expect to pay for them on a low and a high end? Perhaps from a private seller.
The 10 is “harder” because there hasn’t been a public sale in some time, but there is a plethora of information on the 9 as well as several eBay listings (including an active 99 cent auction). Look for sold listings like this. The last sales for the 10 were in the $300-$400 range in 2018 according to Pokemonprice.
Pokemon cards don’t just have a single set price like a Nintendo Switch or other mass produced off-the-shelf consumer goods, nor are they fungible. They are worth whatever price you and a seller agree to transact at.
It will cost whatever the next seller is willing to sell it for.
When scarce items don’t have sales for years at a time, there is no set price, or even a way to estimate. Sometimes you have to be the one to make an offer above the last data point and set the new price, if it’s an item you really want.