Free lunch?

If, like me, you're always on the lookout for a bargain, you may - also like me - be somewhat confused about the various ways in which you can get software for nothing. So, here's a quick rundown:
Demo version - what it says. For you to try out. Normally fully functional but time limited.
Crippleware - similar, but usually not time limited. Instead there will be features (probably important ones like saving or printing) which don't work.
Shareware - try before you buy. Similar in concept to a demo version, and the idea is that you have to pay a fee if you want to keep it beyond a certain length of time, but quite often you are put on your honour to pay if you wish to continue to use it, and nothing happens if you don't.
Freeware - completely free. The conditions which come with it may place restrictions on its use, but there is never any question of payment.
Open Source - not only free but also gives you access to the source code, which you are at liberty to amend and develop for your own use, or pass on to others.

So - good hunting!