Definitions.

freeware (2 examples you use)
-Computer software distributed without charge.
2 exapmles are: Flicker; photobucket

shareware (2 examples you use)
-Computer software distributed without initial charge but for which the user is encouraged to pay a nominal fee to cover support for continued use.
2 examples are: Picnik; iTunes

open source (do you use?  if so, give an example)
- Intellectual property, esp computer source code, that is made freely available to the general public by its creators

commercial software (2 examples you use)
-Any software developed to be sold to consumers
2 examples are: jamster; Vision for Apache