private uni : UTAR, Curtin University, Monash, Nottingham
public uni : UTM, UM, UTM, UKM

both uni need money, jz the matter of amount. private uni may need up to 40K per year while public uni only a few K per year.. so public uni is very very cheap compared to private.

pre-U is jz like form 6/stpm. it;s a course that prepare u for the uni that u gonna enter after u finish it. only that the time taken is shorter and it's private and more expensive.

the routes should be :
1.SPM>>STPM>>Public uni
2.SPM>>STPM>>private uni
3.SPM>>Pre-U>>Private uni
4.SPM>>diploma>>private uni

all those private uni i mentioned means it's degree level.
there is also:

SPM>>private uni

usually after spm, student will enrol into the uni for the Foundation( 1 year). after completing, they can direct go in degree level.

hope this helps~