I'm selling this two-person bike. Great quality and good condition. Nice for a bike ride with a friend. 
HI, i'm interested in buying your tandem bike. But I think the asking price is a bit high.
What price range are you thinking of?
I'm more at the $525 range.
I'd prefer not to go below $600
$600 is fair, but I can't go that high. Also, there aren't many people who are interested in tandem bikes nowadays, so I feel like the bike may sit for awhile if you don't take my offer.
True. I'll cut you a deal. How about this, if you ride this bike with me around the block, I'll sell it to you for $500. I never got to properly use it because I have no friends. 
Aww, I am more than happy to go for a bike ride with someone with no friends. $500 it is.