Photoshop is the Software made by Adobe (Company Name). There are different versions, CS2 (Creative Suite 2) being the most recent version, Photoshop CS, 7, 6, 5 etc.
The Macromedia Company (which was recently bought off from Adobe) has
Fireworks , which is mainly used for web graphics, such as the Avatars and Signatures here in UM, web banners etc.
There are a few others, like the
Corel Suite as Angrycrustacean posted, that also includes the Paintshop Family, Corel Painter, Graphics Suits, etc.
I'm not sure about the comparison of the price ranges, but you can buy affordable softwares that are consumer-friendly for under $100. However for intermediate and professional users, the price range can extend to $100-1000+ for the suite, which is a collection of softwares.
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I hope I don't sound like a know-it-all. I'm researching the price range and the softwares as I'm typing this out. Hope this helps