I've flipped a couple bikes & parts on CL.
I now put in my ad that-
"Cash only. Please bring correct amount".
I think that also lets them know that I'm not interested in haggling.

I also don't give them details about where I live on the first email. About "X" blocks from a local landmark/store is all they get on my initial answer. I ask them to set a time (within my quite flexible time frame) if they are still interested and I'll respond with the address.
I don't deal over the phone.

IF you do a lot of CL, I'd suggest setting up a different (free) email account, especially if your "real" name is part of your email address. Hotmail, Gmail...