Here is the plan for the upcoming Trading screen.
The player can filter the available item list via the category buttons (toggleable). Selecting a row will bring up the item details onto the right part. Apart from the image and description, the list of equipment types and quantities are listed. The player can instantly buy items by clicking on the Buy buttons.
Due to the way the inventory works in Open-IG, equippable ships and stations won't be added to the inventory but deployed near the specified planet. If the target planet is full of stations, the purchase is rejected with a warning. The "deliver to" choicebox will be populated with all the player's planets or just the ones with military spaceport (?). Buying fighters and tanks will be deployed onto the target planet if the capacities permit (excess will go into the global inventory), or can be sent into the inventory directly with "deliver to". Buying other weapons and equipment will always go to the global inventory.
Buying units affects their market price, which is updated frequently. To buy multiple units with the same price, the game should be paused.