So I haven't bought pins off CL but I have bought tons of video games off it and the same principles apply. Respond quick,ask a few questions,agree on a price, set up a time. Buyers are flaky all the time,I've asked questions and told them I'm not interested if I don't like what I hear. I dont expect them to hold it for me, as they're not a business looking for repeat customers.

I think you need to rethink your role as buyer. They're not supposed to be swooning you in a "customer is always right" style. You shouldn't be expecting them to hold pins if all you said is "I'd buy it for $X" with no further details. Also, unless youre chatting it up, they don't care about ancillary details in your life. If anything it makes you a worse buyer.

Who would you rather sell to?
Guy A: "ill be there tomorrow 5 pm, cash in hand, to pick it up after a quick look over"

Guy B: "I can probably make it this weekend, but my lawn mower broke, so Idk how long that will take, but maybe the weekend after that. Also, I won't do a deposit cause you're a stranger and I dont trust you, but I want you to hold the game indefinitely and trust ME to pick it up at my convenience"

I seriously think you'll be less disssapointed if you get out of the mindset that this is a business, and think more of it two parties making a trade. While I understand videogames are a lot cheaper, easier to transport etc.. You will 100% have more success the more expedient you are.