You can do this with AutoCorrect, but why would you. If you go to
Insert>Symbols and select the degree symbol or the cents symbol, you will
find that they already have shortcuts assigned to them.
Degree = Ctrl+Sht+@, space (that is hold down Control and Shift key whilst
pressing the @ sign, release and press c)
Cents = Ctrl+/, C (hold down Control key and press /, release and press c)
If there are other symbols you need that don't have a shortcut assigned,
go to Insert, Symbol, select the Symbol and choose Shortcut Key where you
can assign your own shortcut.