How do people say, "I don't want to buy your stuff." when fundraising.

They just pretend they didn't hear me, or pretend to be on their cell phone.

I'm usually the one doing the refusing =P

And it goes something like this:
"Huh? Your selling something? Nope, not interesting. Huh, why are you still here? *slams door*"

I generally just say I'm not interested. Nobody has yet pushed it beyond that.

Well, usually it's something stupid that you don't need, that and fundrasiers(/door-to-door salesmen) other than girl/boy scouts, obviously, have gotten bad reputations.

I just don't like it when Jehova's Witnesses come knocking. I don't have a problem with Mormons, or anything, just... jeez.

Advertising your religion like that is as low and desparate as you can get...