I'm kinda new to supreme I found a dead kennedys work jacket on eBay for 260 is that a good price? If I wait will the prices lower or will they just all sell?Prices will go down a month after the drop. That's when the resellers who overpriced their items are trying just to get rid of it. eBay prices are always higher than forum prices, so check the forums. Likely 2 weeks after the drop is when people will begin posting it to forums, because it just came in the mail. They'd be selling for various reasons: wrong size, don't like it, shouldn't have bought since they need to pay rent, etc. I would wait on it if you plan to buy resell.
However be aware, if you wait months after the drop, that's when the price will go back up due to rarity of the item, but only if it's a grail. Time will only tell you that.