My herb garden is looking quite ratty so before everything goes to seed or dies, I have made some cuttings and placed them in water.  The idea is to get them to grow some roots and be able to replant them into prepared soil.  Basil works really well with this method of propagation.
Not every piece will grow roots so make sure you start with more plants than what you will need.  You can always pass extras on to family and friends.
This is an excellent way to save money and you will get a real kick out of it.

Do you love to get plants for free?