It depends on what you like, or what you think you might need. If you like reading, you can ask for a book. If your someone dedicated to study's, you might ask for a laptop, to help you research/play games online/chat with friends. Just make sure not to ask for something that is to expensive.
Oh what 16 year old girl wouldn't look hot cruising around in a brand new 2013 Ford Mustang convertible? So go ahead and ask for that! If you were my kid I would give you one in 1:24 scale, but if you ask really nice and flutter those pretty eyelids maybe daddy will buy you one in 1:1 scale! (And all your girlfriends will just LOVE you!)
I think you should either ask for money or a new phone, laptop, or something like that. I suggest not to ask for a car until ur close to 17 because i think ur asking a little to much. But it depends on ur parents personality or something.. If your parents treat your poorly i suggest not to if you parents are broke, dnt ask, if ur parents giv u whtever most of the time or somthingand they are really nice, i suggest u ask. It depends on your parents.. yah. But if you are REALLY responsible and mature i guess whether you parents are an ok or really nice or whatver i think they thinnk you deserve it and they will give it to as a suprise.