I know it isn't possible all the time, but I endeavour to pay as soon after I commit to buy something as possible. 12 hours is more than generous in my opinion. If the buyer knows he will be unable to do paypal for longer than that time, he should at least have the decency to tell the seller.

There is more of a relaxed attitude to selling ethics here than any other forum I've been on. On most others, if a buyer commits to an item, it is held buy the seller until payment, not sold to someone else who had came up with the money sooner. I really don't agree with those who do that.