Gillette Open Comb - Old or New
Gillette Adjustable - Toggle, Fatboy, Slim or Super Adjustable
Gillette Tech
Gillette Aristocrat
Merkur 37 Slant
EJ/Muhle 89
All of those except the Toggle, Fanboy and Aristocrat can be easily found for well under $100 and they're all absolute classics in my opinion and will give you a very well rounded experience with de razors.