I’m still against the idea of an all interplanetary, everything shown on one screen, auction house…
Especially not one that doesn’t require you to go to the shop to purchase a required item. Footfall is not just given to shop owners… but every beacon you pass through along the way!
We also need to remember that the Tax value from shop stands was originally intended to be a customisable figure set by the capital of each world - this hasn’t yet been implemented, and I don’t know if it still will be, but it at least needs to be taken into consideration.
That said, however, I think it might worth exploring some of the potential options this concept art presented …
Maybe these could be linked to all shop stands / request baskets within a beacon and the signal is only active if there are items to sell or coin in the baskets.
Some (random) ideas to then gain visibility of those signals could be-
- They could appear as a coloured marker on an atlas with a socketed item (would work better for selling, but not so well for buying as you’d already need to have one of an item before you try to buy).
- They could be linked to “signal receiver” game asset which has visibility of all transmitted signals, either at a settlement or planetary level (this could also potentially display prices (maybe ?)). Then if a small fee is deposited, it could set your custom waypoint so you could get to the items you want. The fee could go to the creator of the signal receiver asset as an incentive to craft it and make it accessible.
Maybe you require a location signal of different types to signify what types of items you are selling 
(I’m just throwing ideas around now).
What other things would people suggest along these lines? Personally, I really do not want to see another in game menu to handle this stuff, so an in game way would be much better imo.