How long after I quit does a company have to send me my last paycheck?

This really can be affected by whether you are salaried or hourly. It may take two regular paydays to get your money unless there are other issues involved but not shared.

It should be done at the same time the other employees get paid, I would assume anyway!

It really varies with the industry. For an example, a teacher may get paid for up to 3 months after the school year ends. It is common for salaried people to have their pay prorated over an entire year even if the work load varies. Habby will need to fill in a few blanks for us.

Normally what happens, is when would you normally get paid for that week, so that payday is when you should get that check,

If there are a lot of books to balance, expense accounts, sales commissons and the such, it may be the following pay period