I would recommend a nice graded 63 to 65 CC morgan dollar. Of course this depends on the price range you need.
I'd buy a 1916-D Merc if you like Mercs. Or a nice CC Morgan like stated on the last page. But if I were to choose, I'd get the 16-D Merc, because you can get a nice CC Morgan in MS-64 or 65 for less, just in a more common date. Or like Merc Crazy said, I like his idea of a nice Proof Merc.
Warning. ff-topic: Alert. I had $1000 bucks in my pocket in 1986 from graduation. I desperately wanted a Fender Electric guitar but since I needed transportation more than a new guitar I ended up getting this instead. 1974 DOHC Yamaha. Good times. I blew up the engine 3 years later.
Are you graduating from the 12th grade? Pick out a nice CC Morgan dollar under $200 or maybe a proof Morgan under $2,000.