API:GetBagItemLink

Returns an itemlink of what's in your bag at the inventoryIndex.

link = GetBagItemLink(inventoryIndex);

Parameters[]

link: string - A string formatted with color and a link that causes the item to pop-up when clicked.

Links the first bag item slot in Backpack I:

SendChatMessage(GetBagItemLink(GetBagItemInfo(1)),"SAY")

Bag indexes used for GetBagItemInfo are not the same as the Inventory Indexes used by UseBagItem, GetBagItemLink, and PickupBagItem
Inventory Indexes 1-50 are in the Item Shop Backpack and run sequentially from left to right, top to bottom. It is possible these could move like the backpacks, but has not been observed.
Inventory Indexes 51-55 are in the Arcane Transmutor and start with 51 in the middle, and from there run sequentially from left to right, top to bottom. It is possible these could move like the backpacks, but has not been observed.
Inventory Indexes 56-60 are invisible slots in the Arcane Transmutor. You can put/use stuff in here, but if you do an arcane combine, it will all disappear!
Inventory Indexes 61-90 are in Backpack I, but seem to move around very session.
Inventory Indexes 91-120 are in Backpack II, but seem to move around very session.
Inventory Indexes 121-150 are in Backpack III, but seem to move around very session.(unconfirmed)
Inventory Indexes 151-180 are in Backpack IV, but seem to move around very session.(unconfirmed)
Inventory Indexes 181-210 are in Backpack V, but seem to move around very session.(unconfirmed)
Inventory Indexes 211-240 are in Backpack VI, but seem to move around very session.(unconfirmed)