[carpeperdiem]

Do you absolutely have to link your cart with the actual item (as far as which item gets shipped)?

The reason I ask is you could do this:

Product 1
variant: condition (flawless, very good, good, been around the block)

You can have 4 SKUs for Product 1. Your inventory will know how many of each variant you have, and not allow a sale of a specific variant if out of stock.

YOU would have to have some kind of databse or tracking system that logs incoming products, ages them, assigns a unique identifier, etc... BUT the SKU that you sell never changes...

Here's an example from my business: every now and then we will change suppliers for a component or part (and the final product may vary in appearance slightly) but our customers will never know this -- we have unique vendor part numbers and finished goods part numbers -- and it only gets tricky when we change a vendor and the product changes slightly, and we want to burn through all the old stock before we sell the new stock... our accounting program allows us to specify locations for the inventory, so we use that to track it.

SO -- my suggestion is to keep your SKUs in the cart static, adjust your inventory as items come in or out, and figure out how to age your inventory, so that the first in is first out. You're not re-inventing the wheel -- it's pretty common in many businesses.

Your cart does not have to be connected to the actual product inventory, only the quantities must reconcile.

Just my opinion. Hope this helps.

Jeremy