As a suggestion, when several people are interested in an item you are offering, don't necessarily give/sell it to the first person to respond. How about waiting 24 hours and then choosing someone - maybe at random, or maybe the easiest to arrange the collection/delivery with?
That would make it less of a race and give those who weren't online when you posted a chance too.
This is just a suggestion of course; it's up to you who gets it and how you decide.
