Believe me, I know the frustration of completing something incomplete and only wanting the pieces you need and nothing more. This is why when I buy games I always buy them with cases and manuals. All too often the only way to get the case and manual later is to buy the whole game again...which is what I should have done in the first place. I so have some loose PCE games, but they were all given to me for free.
I have this policy with G1 Transformers too. If you buy a guy without his gun...how the f*ck are you going to get just the gun? That's the first part that gets lost!