Freeware
Freeware is software that you can download for free off of the internet. Since it is free it may not offer all the features that a paid version may offer.
Shareware
Shareware is software that is readily available to download online for a free trial evaluation. At the end of the trial period the user is bound by the electronic user licence agreement to either uninstall the software, or pay for its continued use.
Commercial/proprietary
Proprietary software is software that is owned by an individual or a company (usually the one that developed it). There are almost always restrictions on its use, and its source code is almost kept secret.