I know it can be so annoying. As for the lowball offers at the door my answer is always "no". I just say I have lots of ppl interested and will sell to somebody else if they don't take it. I think what has annoyed me the most were ppl showing up saying "oops, I guess I only brought 40$ for the item(even though I was asking 50$), is that ok?" ARGH! It's such BS. I don't put up with that nonsense anymore some people!