It’s pretty easy to figure out what the seller is “fishing” for.
Sellers often ask for about 10% more than they will actually accept.
It’s a good idea to know the new and used values of what you are shopping for.
Once you know those things, look for what you want on CL, and narrow down your options.
My rule of thumb is simple.
If a popular item sells for $1000 new, second hand it should sell for 50-60% of that, $500-600, roughly.
Look for reasonable prices, a lot of CL sellers are delusional.
OBO usually means another 10-15% less may be accepted.
Articles that have been available for awhile are extra vulnerable to lower offers.
Don’t lowball or “grind” sellers, it’s annoying, rude, disrespectful, and rarely works.