What's the going value of the following 2 10oz coins...?

[AndyC44]

I've been looking around Google for the going prices for the '2020 30th anniversary 10oz kookaburra' and the '2017 Queen's beasts 10oz bull'. I'm finding quite wildly varying prices from different sources, some of which may well be outdated. The reason for asking is because I have 2 of each, and I'm curious to know the current value for my own records (who doesn't have a silver spreadsheet!?) firstly. Also, if I decide to sell one of either I have no idea what a fair price is. I'm very much out of the loop in these things.

I know certain items carry a premium, sometimes a stupid high premium. Some have a premium for a short time, then lose it. And some carry no premium worth mentioning. These things sometimes seem arbitrary from what I know.