Sure, ask for a deal, it can't hurt. But if the sales person doesn't know you or remember you, don't take it so personal.

Sales people have bad days too. And they're the bottom of the food chain in some businesses, even if they're all you see. Whether or not a deal is given can be based on how good the business is doing that day, the relationship that particular sales person has with the higher ups, or simply the person's (or the boss' !) mood.