First come, First sold

I always strive to be fair, kind, generous, and supportive to others and their needs regardless if I know you or not. Unfortunately, I've found this to be a negative when it comes to selling things. Case in point, I had a yard sale once and I was selling a pretty decent high chair or similar item for $20. One could argue that was too much to ask at a yard sale, but honestly, I keep my stuff in primo condition and it was reasonable in my opinion. So a prospective buyer appears, and marvels at my goods, widdles me down a bit prior to realizing they have no cash on them...and therein lies my problem. The goodness in me shines as I agree to place the item on hold til they return.

I'm sure you know what's coming next. They don't return. And what I've learned is that I don't want to extend the kindness to others now because I fear it will be at my own expense. My internal debate continues to this day as far as whether or not I should be doing this for others, because surely there are some deserving people that would follow through on their promise and be considerate.

So that brings me to the online dilemma, my husband and I are active craiglisters (he's a borderline addict which I find incredibly funny) and what I've noticed is that people that call first expect first dibs, even if someone wants stop by sooner to see and maybe buy what we're selling.
And the reality is that I feel bad that even when someone says, "Look, I'll pay, consider it sold." I have to say, sorry, we'd love you to have it but we have to sell to the first buyer that comes by. All that said, I'm really curious what other seller's takes are. Do you have a first come, first sold approach? Have you been burned too? (I don't mean by the Craigslist scammers.)

Comments are encouraged and welcomed!