Adobe Photoshop: up to $650 - Trial version available
The best imaging software, Adobe Photoshop is still the standard by which all others are measured. If you can afford Photoshop, then the money will be well spent.
- standard professional imaging application
- The best looking alogrithms and filters
- Free to try, up to $650 to buy
- Older versions available if you're on a budget
- available for Mac and Windows
Finding Photoshop for under $100
You may be able to find some cheaper (older) versions on Ebay. An older version of Photoshop may not have all the latest features, but would be well worth the money you would pay for it (under $100 I would imagine).
Photoshop is still the best photo editing software available and can be used for all examples on this site.
Adobe Photoshop homepage.