To be honest, they are all pretty rare now as they aren't made any more. However, the Joker seems to be amongst the rarest! :)
The Fisherman
The rarest lego minifigure for series 5 is the LUMBERJACK
The most rare minifigure in series 8 is the red cheerleader!
rarest minifigure is boat
Probaly the genie
Probably proffer quirell
The rarest Lego Star Wars piece is probably the 10k golden C3PO. Made out of real gold, there are very few in the world.
The modern minifigure was introduced in 1978.
buy
On ebay.com
no
basiclly you cant only if that guy sells you his own. Jango is one of the rarest minifigure in the world. I have one and i spended more than 100 us to get it.