serpent hook island islands

If the buyer's economy level is below 25, the item will be given via trade (you have to wait for the seller to come on)
If the buyer's economic level is above 25, the goods will be given via vending (anytime, just wait for the seller to come on)
If you are 1 hour+ late due to the seller's error, you can request a bonus (as long as it doesn't exceed the items purchased)