When I sign up for any shop, I consider what the value is for *me.* If I am happy with the compensation, I don't care if the MSC is raking in billions. If the MSC cannot offer me enough to entice me to do the shop without taking a loss, that's not my problem. I don't do the shop unless they are willing to take the loss. Either they need to find somebody who finds more value in the shop than I do, or they need to have a talk with their client.
As for a retail item.... If I am looking to purchase a $20 gadget and I can do so as part of a $20 shop reimbursement, that shop has a $20 value to me. It's not my concern of the client only spent a quarter on it. To me, it was a $20 shop. However, if I am not looking to purchase said item, the shop has zero value to me.
Hard work builds character and homework is good for your soul.