Can I limit how many applications a person can register?

Settings > Registration > Registration limit and Settings > Categories

In Settings > Registration > Registration limit, you can choose between allowing "Multiple applications per registration" and "One application per registration".

If you choose to allow "Multiple applications per registration" you also get the option to set an "Application limit per registration".

In addition to this, when creating your program categories in Settings > Categories you can set "Application limit for the category per registration" for each category.