You can wheel and deal. End of the day gets you the best price because people want to sell.Begining of the day gets you best selection. But if its a "must have" and "not too many of" you might have to jump on it. You can also give them a chunk of money and workout a payment.
They'll have everything you need. Take pics. I usually bring a vid cam so i can go back and check the video if there is something else i want.