I try to pay immediately after I win an auction, but sometimes I'll win something and pay for it in a day or two, when I'm more flush (after I get paid or receive payment for an item I sold). I always respond to the first invoice from the seller and let them know when I'm planning to pay (always, of course, within the 4 days Ebay allows buyers post-sale), or I pay immediately (barring the two scenarios Iris described further up in this thread). I don't mind when buyers do this when they win my items, though sometimes it does throw off my post-office trips

- as long as they pay within 4 days, I'm cool with it, though I REALLY appreciate communication about when I can expect the payment.