Getting Expelled from school means that the student is barred from going to that school for a specific period of time.
The school can allow you to come back to the school if they decide too but most times once becoming expelled from a certain school the student will have to find another school to transfer too.
Suspension from school happens first and then expulsion then the last is the being expelled from school which is the more severe punishment.
However being barred from school through being expelled doesn't seem like punishment to me since I hated school and not being allowed back in school would be great.
Although it just means that you'll be unable to graduate and get the diploma you need to get jobs with in the future.
However there's always the option of building your own business and working for yourself where you don't need a diploma.
In fact even though I have a diploma and used to work for an office I now work full time at home blogging and I don't need a diploma for blogging to make money.